Minimally invasive tooling for delivery of interspinous spacer

ABSTRACT

A plurality of individual tools is provided where each tool is uniquely configured to perform a step or a portion of a step in a novel procedure associated with the implantation of a stabilizing device (e.g., an interspinous spacer) for stabilizing at least one spinal motion segment. The tools are usable individually, or more preferably as a tooling system in which the tools are collectively employed to implant an interspinous spacer, generally in a minimally invasive manner. For example, each of the tools is arranged with coordinated markings and/or other features to ensure consistent depths of insertion, proper orientation of the tools with respect to each other or an anatomical feature of the patient, and precise delivery of the spacer to maintain safe positioning throughout the implantation procedure.

TECHNICAL FIELD

The present invention is related to treatment of spinal disorders andpain and, more particularly, to minimally invasive tooling for deliveryof an interspinous spacer device.

BACKGROUND

FIGS. 1 and 2A illustrates a portion of the human spine having asuperior vertebra 2 and an inferior vertebra 4, with an intervertebraldisc 6 located in between the two vertebral bodies. The superiorvertebra 2 has superior facet joints 8 a and 8 b, inferior facet joints10 a and 10 b, and spinous process 18. Pedicles 3 a and 3 b interconnectthe respective superior facet joints 8 a, 8 b to the vertebral body 2.Extending laterally from superior facet joints 8 a, 8 b are transverseprocesses 7 a and 7 b, respectively. Extending between each inferiorfacet joints 10 a and 10 b and the spinous process 18 are laminal zones5 a and 5 b, respectively. Similarly, inferior vertebra 4 has superiorfacet joints 12 a and 12 b, superior pedicles 9 a and 9 b, transverseprocesses 11 a and 11 b, inferior facet joints 14 a and 14 b, laminalzones 15 a and 15 b, and spinous process 22.

The superior vertebra with its inferior facets, the inferior vertebrawith its superior facet joints, the intervertebral disc, and sevenspinal ligaments (not shown) extending between the superior and inferiorvertebrae together comprise a spinal motion segment or functional spineunit. Each spinal motion segment enables motion along three orthogonalaxes, both in rotation and in translation. The various spinal motionsare illustrated in FIGS. 2A-2C. In particular, FIG. 2A illustratesflexion and extension motions and axial loading, FIG. 2B illustrateslateral bending motion and FIG. 2C illustrates axial rotational motion.A normally functioning spinal motion segment provides physiologicallimits and stiffness in each rotational and translational direction tocreate a stable and strong column structure to support physiologicalloads.

Traumatic, inflammatory, metabolic, synovial, neoplastic anddegenerative disorders of the spine can produce debilitating pain thatcan affect a spinal motion segment's ability to properly function. Thespecific location or source of spinal pain is most often an affectedintervertebral disc or facet joint. Often, a disorder in one location orspinal component can lead to eventual deterioration or disorder, andultimately, pain in the other.

Spine fusion (arthrodesis) is a procedure in which two or more adjacentvertebral bodies are fused together. It is one of the most commonapproaches to alleviating various types of spinal pain, particularlypain associated with one or more affected intervertebral discs. Whilespine fusion generally helps to eliminate certain types of pain, it hasbeen shown to decrease function by limiting the range of motion forpatients in flexion, extension, rotation and lateral bending.Furthermore, the fusion creates increased stresses on adjacent non-fusedmotion segments and accelerated degeneration of the motion segments.Additionally, pseudarthrosis (resulting from an incomplete orineffective fusion) may not provide the expected pain-relief for thepatient. Also, the device(s) used for fusion, whether artificial orbiological, may migrate out of the fusion site creating significant newproblems for the patient.

Various technologies and approaches have been developed to treat spinalpain without fusion in order to maintain or recreate the naturalbiomechanics of the spine. To this end, significant efforts are beingmade in the use of implantable artificial intervertebral discs.Artificial discs are intended to restore articulation between vertebralbodies so as to recreate the full range of motion normally allowed bythe elastic properties of the natural disc. Unfortunately, the currentlyavailable artificial discs do not adequately address all of themechanics of motion for the spinal column.

It has been found that the facet joints can also be a significant sourceof spinal disorders and debilitating pain. For example, a patient maysuffer from arthritic facet joints, severe facet joint tropism,otherwise deformed facet joints, facet joint injuries, etc. Thesedisorders lead to spinal stenosis, degenerative spondylolithesis, and/oristlunic spondylotlisthesis, pinching the nerves that extend between theaffected vertebrae.

Current interventions for the treatment of facet joint disorders havenot been found to provide completely successful results. Facetectomy(removal of the facet joints) may provide some pain relief; but as thefacet joints help to support axial, torsional, and shear loads that acton the spinal column in addition to providing a sliding articulation andmechanism for load transmission, their removal inhibits natural spinalfunction. Laminectomy (removal of the lamina, including the spinal archand the spinous process) may also provide pain relief associated withfacet joint disorders; however, the spine is made less stable andsubject to hypermobility. Problems with the facet joints can alsocomplicate treatments associated with other portions of the spine. Infact, contraindications for disc replacement include arthritic facetjoints, absent facet joints, severe facet joint tropism, or otherwisedeformed facet joints due to the inability of the artificial disc (whenused with compromised or missing facet joints) to properly restore thenatural biomechanics of the spinal motion segment.

While various attempts have been made at facet joint replacement, theyhave been inadequate. This is due to the fact that prosthetic facetjoints preserve existing bony structures and therefore do not addresspathologies that affect facet joints themselves. Certain facet jointprostheses, such as those disclosed in U.S. Pat. No. 6,132,464, areintended to be supported on the lamina or the posterior arch. As thelamina is a very complex and highly variable anatomical structure, it isvery difficult to design a prosthesis that provides reproduciblepositioning against the lamina to correctly locate the prosthetic facetjoints. In addition, when facet joint replacement involves completeremoval and replacement of the natural facet joint, as disclosed in U.S.Pat. No. 6,579,319, the prosthesis is unlikely to endure the loads andcycling experienced by the vertebra. Thus, the facet joint replacementmay be subject to long-term displacement. Furthermore, when facet jointdisorders are accompanied by disease or trauma to other structures of avertebra (such as the lamina, spinous process, and/or transverseprocesses) facet joint replacement is insufficient to treat theproblem(s).

Most recently, surgical-based technologies, referred to as “dynamicposterior stabilization,” have been developed to address spinal painresulting from more than one disorder” when more than one structure ofthe spine have been compromised. An objective of such technologies is toprovide the support of fusion-based implants while maximizing thenatural biomechanics of the spine. Dynamic posterior stabilizationsystems typically fall into one of two general categories: posteriorpedicle screw-based systems and interspinous spacers.

Examples of pedicle screw-based systems are disclosed in U.S. Pat. Nos.5,015,247, 5,484,437, 5,489,308, 5,609,636, 5,658,337, 5,741,253,6,080,155, 6,096,038, 6,264,656 and 6,270,498. These types of systemsinvolve the use of screws that are positioned in the vertebral bodythrough the pedicle. Certain types of these pedicle screw-based systemsmay be used to augment compromised facet joints, while others requireremoval of the spinous process and/or the facet joints for implantation.One such system, the Zimmer Spine Dynesys® employs a cord which isextended between the pedicle screws and a fairly rigid spacer which ispassed over the cord and positioned between the screws. While thissystem is able to provide load sharing and restoration of disc height,because it is so rigid, it does not effective in preserving the naturalmotion of the spinal segment into which it is implanted. Other pediclescrew-based systems employ articulating joints between the pediclescrews. Because these types of systems require the use of pediclescrews, implantation of the systems are often more invasive to implantthan interspinous spacers.

Where the level of disability or pain to the affected spinal motionsegments is not that severe or where the condition, such as an injury,is not chronic, the use of interspinous spacers are preferred overpedicle based systems as they require a less invasive implantationapproach and less dissection of the surrounding tissue and ligaments.Examples of interspinous spacers are disclosed in U.S. Pat. Nos. Re.36,211, 5,645,599, 6,149,642, 6,500,178, 6,695,842, 6,716,245 and6,761,720. The spacers, which are made of either a hard or compliantmaterial, are placed in between adjacent spinous processes. The hardermaterial spacers are fixed in place by means of the opposing forcecaused by distracting the affected spinal segment and/or by use of keelsor screws that anchor into the spinous process. While slightly lessinvasive than the procedures required for implanting a pediclescrew-based dynamic stabilization system, implantation of hard or solidinterspinous spacers still requires dissection of muscle tissue and ofthe supraspinous and interspinous ligaments. Additionally, these tend tofacilitate spinal motion that is less analogous to the natural spinalmotion than do the more compliant and flexible interspinous spacers.Another advantage of the compliant/flexible interspinous spacers is theability to deliver them somewhat less invasively than those that are notcompliant or flexible; however, their compliancy makes them moresusceptible to displacement or migration over time. To obviate thisrisk, many of these spacers employ straps or the like that are wrappedaround the spinous processes of the vertebrae above and below the levelwhere the spacer is implanted. Of course, this requires some additionaltissue and ligament dissection superior and inferior to the implantsite, i.e., at least within the adjacent interspinous spaces.

With the limitations of current spine stabilization technologies, thereis clearly a need for an improved means and method for dynamic posteriorstabilization of the spine that address the drawbacks of prior devicesand associated delivery procedures and tooling. In particular, it wouldbe highly beneficial to have a dynamic stabilization system that reliesupon an implantation procedure using minimally invasive tooling. Itwould be additionally advantageous if the implantation procedure werereversible.

SUMMARY

A plurality of individual tools is provided where each tool is uniquelyconfigured to perform a step or a portion of a step in a novel procedureassociated with the implantation of a stabilizing device (e.g., aninterspinous spacer) for stabilizing at least one spinal motion segment.The tools are usable individually, or more preferably as a toolingsystem in which the tools are collectively employed to implant aninterspinous spacer, generally in a minimally invasive manner. Forexample, each of the tools is arranged with coordinated markings and/orother features to ensure consistent depths of insertion, properorientation of the tools with respect to each other or an anatomicalfeature of the patient, and precise delivery of the spacer to maintainsafe positioning throughout the implantation procedure.

DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in conjunction with the accompanying drawings. It isemphasized that, according to common practice, the various features ofthe drawings are not to scale. On the contrary, the dimensions of thevarious features are arbitrarily expanded or reduced for clarity.Included in the drawings are the following figures:

FIG. 1 is a perspective view of a portion of the human spine having twovertebral segments;

FIGS. 2A, 2B and 2C illustrate left side, dorsal and top views,respectively, of the spinal segments of FIG. 1 undergoing variousmotions;

FIGS. 3 and 3A are pictorial views of an illustrative target needle andinner puncher, respectively;

FIG. 4 is a pictorial view of an illustrative K-wire;

FIG. 4A is a detailed view of an circumferential notch forming a groovein an illustrative K-wire;

FIG. 4B is a detailed view of a circumferential band in an illustrativeK-wire;

FIG. 5 is a pictorial view of an illustrative K-wire clamp;

FIG. 5A is a pictorial view of an illustrative K-wire clamp arrangedwith optional sensor and alarm functions;

FIG. 6 is a pictorial view of a first illustrative dilator;

FIG. 6A is a detailed view of the distal end of the first illustrativedilator shown in FIG. 6;

FIG. 7 is a pictorial view of a second illustrative dilator;

FIG. 7A is a detailed view of the distal end of the second illustrativedilator shown in FIG. 7;

FIGS. 8, 8A, 8B and 8C show various pictorial views of an illustrativemounting bracket in various alternative arrangements;

FIGS. 8D-L show various pictorial views of an illustrative mountingtower;

FIGS. 9, 9A and 9B are a side, and two perspective views, respectively,of an illustrative cannula;

FIG. 10 is a pictorial view of an illustrative flexible stabilizing arm;

FIG. 11 is a pictorial view of a first illustrative interspinous knife;

FIG. 11A is a detailed view of the distal end of the interspinous knifeshown in FIG. 11;

FIG. 11B is a detailed view of the proximal end of the interspinousknife shown in FIG. 11;

FIG. 11C is a pictorial view of a second illustrative interspinousknife;

FIG. 11D is a detailed view of the distal end of the interspinous knifeshown in FIG. 11C as inserted through a cannula and into theinterspinous space;

FIG. 12 is a pictorial view of a core cutting portion of a firstillustrative interspinous reamer;

FIG. 12A is pictorial view of a hole cutting portion of the firstillustrative interspinous reamer;

FIG. 12B is a pictorial view of the hole cutting and core cuttingportions of the first illustrative interspinous reamer in operativeengagement for performing a hole cutting process;

FIG. 12C is a pictorial view of the hole cutting and core cuttingportions of the first illustrative interspinous reamer in operativeengagement for performing a core cutting process;

FIG. 12D is pictorial view of a second illustrative interspinous reamer;

FIG. 12E is a detailed view of the distal end of the interspinous reamershown in FIG. 12D;

FIG. 12F is a detailed view of the distal end of the interspinous reamershown in FIG. 12D as inserted through a cannula and into theinterspinous space.

FIG. 13 is a pictorial view of a first illustrative interspinous gauge;

FIG. 13A is a detailed view of the distal end of an elongated tube inthe interspinous gauge shown in FIG. 13;

FIG. 13B is a pictorial view of a second illustrative interspinousgauge;

FIG. 13C is a detailed view of a sizing scale disposed in interspinousgauge shown in FIG. 13B;

FIG. 13D is a view of the distal end of the interspinous gauge shown inFIG. 13B;

FIGS. 14 and 14A are pictorial views of a first illustrative insertioninstrument;

FIG. 14B is a detailed view of the distal tip of the insertioninstrument shown in FIGS. 14 and 14A;

FIG. 14C is a detailed view of the distal tip of the insertioninstrument shown in FIGS. 14 and 14A in operative engagement with aninterspinous spacer;

FIG. 14D shows a visual scale disposed in the insertion instrument shownin FIGS. 14 and 14A;

FIG. 14E illustrates the deployment positions of an interspinous spacerindicated by the visual scale shown in FIG. 14D;

FIG. 14F is a pictorial view of a second illustrative insertioninstrument;

FIG. 14G is a detailed view of a load/deploy indicator disposed in theinsertion instrument shown in FIG. 14F;

FIG. 15 is a pictorial view of an illustrative ligament splitter;

FIG. 15A is a detailed view of the distal end of the ligament splittershown in FIG. 15;

FIGS. 16, 17, 18, 19 and 20 are illustrations which show variousanatomical locations having relevance to the present tooling andprocedure for implanting an interspinous spacer;

FIGS. 21 and 21A comprise a flowchart of an illustrative procedure forimplanting an interspinous spacer using the tooling shown in FIGS. 3 to15;

FIG. 22 is a pictorial view of the illustrative target needle of FIGS. 3and 3A as inserted through the supraspinous ligament;

FIG. 22A is a detailed view of the distal end of the target needleshowing its approximately centralized position between the superior andinferior spinous processes;

FIG. 23 is a detailed view of the target needle as inserted to anappropriate depth;

FIG. 23A is a detailed view of the illustrative K-wire of FIG. 4 asinserted through the target needle;

FIG. 23B is a detailed view of the alignment of the K-wire to the targetneedle;

FIG. 24 is a pictorial view of an optional use of the illustrativeK-wire clamp of FIG. 5 during positioning of the K-wire;

FIG. 25 is a pictorial view of the first illustrative dilator shown inFIG. 6 as inserted through the supraspinous ligament;

FIG. 25 a is a detailed view of the first illustrative dilator asinserted through the supraspinous ligament to an appropriate depth;

FIG. 26 is a pictorial view of the second illustrative dilator shown inFIG. 7 as inserted through the supraspinous ligament;

FIG. 26A is a detailed view of the second illustrative dilator asinserted through the supraspinous ligament to an appropriate depth;

FIG. 26B is a detailed view of the alignment of the first dilator to thesecond dilator;

FIG. 27 is a pictorial side view of the mounting bracket shown in FIGS.8, 8A, 8B and 8C as inserted over the second dilator;

FIG. 27A is top view of the mounting bracket and dilator with respect tothe mid-line of the spine;

FIG. 27B is a pictorial view of an illustrative docking tower beingloaded over the dilator;

FIG. 27C is a side view of the docking tower and dilator showing apreferred trajectory with respect to the supraspinous ligament andspinous processes;

FIG. 27D is a view of the docking tower and dilator with respect to themid-line of the supraspinous ligament;

FIG. 27E is a view of the docking tower in a deployed position;

FIG. 27F is a detailed side view of the docking tower and dilatorshowing the positioning of the distal end of the dilator just past theanterior side of the supraspinous ligament;

FIG. 28 is a pictorial side view of the cannula shown in FIGS. 9, 9A and9B as inserted through the mounting bracket and over the dilators;

FIG. 28A is a detailed view of the distal end of the cannula showing thealignment of the end channels with the spinous processes;

FIG. 28B is a detailed side view of the distal end of the cannula withrespect to the distal end of the dilator, supraspinous ligament, andspinous processes;

FIG. 28C is a pictorial view of the mounting bracket and cannula showingthe locking orientation of a rotating nut;

FIG. 28D is a pictorial view of the mounting tower, cannula and dilator;

FIG. 29 is a pictorial view of the interspinous knife shown in FIGS. 11,11A and 11B as inserted into the cannula;

FIG. 29A is a detailed view of the initial cut pattern and theorientation of the interspinous knife with respect to the cannula;

FIG. 29B is a detailed view of an optional cut pattern that is oriented45 degrees from the initial cut through rotation of the interspinousknife with respect to the cannula;

FIG. 30 is a pictorial view of the first illustrative interspinous gaugeshown in FIGS. 13 and 13A making a measurement of the interspinous spacebetween the superior and inferior spinous processes;

FIGS. 30A and 30B are pictorial views of the second illustrativeinterspinous gauge shown in FIGS. 13B, 13C and 13D;

FIGS. 31A-F are pictorial views of an interspinous spacer in a varietyof positions;

FIG. 31G is a pictorial view of the insertion instrument of FIGS. 14,14A, 14B, 14C, 14D showing operation of the handle which rotates a shaftin the elongated tube;

FIG. 31H is a detailed view of the distal end of the elongated tube ofthe insertion instrument with rotatable shaft;

FIG. 31I shows a visual scale disposed in the insertion instrument shownin FIGS. 31G and 31H;

FIGS. 31J and 31K are pictorial views of an illustrative interspinousspacer in operative engagement with the insertion instrument shown inFIGS. 31G and 31H;

FIG. 32 is a detailed view of a flat portion of the insertion instrumentin alignment with a flat surface of the cannula that sets a depthindicator of “zero”;

FIG. 32A is a pictorial view of the insertion instrument with loadedinterspinous spacer as inserted through the cannula;

FIG. 32B is a pictorial view of the insertion instrument of FIGS. 14Fand 14G in operative engagement with an interspinous spacer as placedinto the interspinous space in an undeployed position;

FIG. 32C is a pictorial view of the insertion instrument of FIGS. 14Fand 14G in operative engagement with an interspinous spacer as placedinto the interspinous space in a deployed position;

FIG. 33 is a pictorial view of an interspinous spacer as deployed; and

FIG. 34 is a pictorial representation of an image that shows theinterspinous spacer as deployed.

DETAILED DESCRIPTION

Before the subject devices, systems and methods are described, it is tobe understood that this invention is not limited to particularembodiments described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the present invention will be limited onlyby the appended claims.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “aspinous process” may include a plurality of such spinous processes andreference to “the marker” includes reference to one or more markers andequivalents thereof known to those skilled in the art, and so forth.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit, unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassedwithin the invention. The upper and lower limits of these smaller rangesmay independently be included or excluded in the range, and each rangewhere either, neither or both limits are included in the smaller rangesis also encompassed within the invention, subject to any specificallyexcluded limit in the stated range. Where the stated range includes oneor both of the limits, ranges excluding either or both of those includedlimits are also included in the invention.

All publications mentioned herein are incorporated herein by referenceto disclose and describe the methods and/or materials in connection withwhich the publications are cited. The publications discussed herein areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the present invention is not entitled to antedate such publicationby virtue of prior invention. Further, the dates of publication providedmay be different from the actual publication dates which may need to beindependently confirmed.

The present invention will now be described in greater detail by way ofthe following description of exemplary embodiments and variations of thedevices and methods of the present invention. The invention generallyincludes a group of tools arranged for the percutaneous implantation ofan interspinous spacer using an inventive method. A key feature of theinterspinous spacer device is that it is expandable from a low profileconfiguration to a higher profile or operative configuration. Thisdesign allows the device, when in the low profile condition, to bedelivered percutaneously through use of the tooling without requiringthe removal of any portion of the spinal motion segment into which thedevice is implanted.

Each of the tools shown in the FIGs and described in the accompanyingtext are advantageously used as part of as a tooling system to performthe inventive method. That is, the tools are arranged to be used as agroup—each tool in combination with others and/or sequentially asdescribed in detail below. Accordingly, the tools generally areconfigured with coordinated markings and/or features to enable the toolsto be used cooperatively and to ensure consistency of operation duringthe implantation procedure. For example, as noted above and withoutlimiting the invention, each of the tools is arranged with coordinatedmarkings and/or other features to ensure consistent depths of insertion,proper orientation of the tools with respect to each other or ananatomical feature of the patient, and precise delivery of the spacer tomaintain safe positioning throughout the implantation procedure.

However, while use of the tools as a tooling system is preferable insome applications of the invention, it is emphasized that each tool mayalso be beneficially and advantageously utilized alone or in subsetcombination with other tools, but without using all of the tools in thetooling system. Thus while the utilization of the entire set of tools inthe tooling system is often beneficial in many applications, it is notmandatory.

In addition, each of the tools shown in the FIGs and described in theaccompanying text are advantageously utilized to perform the inventivepercutaneous spacer implantation in a minimally invasive manner so as tominimize the affect of the procedure on the patient's tissues and, inparticular, the supraspinous ligament. Utilization of such minimallyinvasive techniques can shorten the procedure's time and speed recoveryby the patient. However, the application of the tools in a minimallyinvasive manner is not a requirement in order to realize many of thebenefits provided by the tooling.

Referring now to FIGS. 3 and 3A, pictorial views of an illustrativetarget needle 305 and inner puncher 312 are respectively provided. Thetarget needle 305 and inner puncher 312, when assembled (e.g., locked)together, function to place a guidewire (e.g., a K-wire) through thepatient's skin into an area which neighbors a vertebral segment ofinterest. Accordingly, target needle 305 and inner puncher 312 areconfigured to penetrate the supraspinous ligament and other tissue.Target needle 305 and inner puncher 312 are preferably disposable tools(i.e., arranged as single use instrumentalities in most applications ofthe invention).

Both the target needle 305 and inner puncher 312 are arranged withgraspers on the proximal ends as indicated by reference numerals 318 and321. Target needle 305 further includes wings 325 that are arranged tofacilitate gripping of target needle 305 by an operator.

Target needle 305 includes a hollow needle portion 327 that is arrangedto removably receive a needle portion 330 of the inner puncher 312,typically in a close-fitting manner. That is, the outside diameter ofthe needle portion 330 is sufficiently close in dimension to the innerdiameter of the hollow needle portion 327 so that the inner puncher 312is substantially radially fixedly positioned once needle portion 330completes its slideable engagement with hollow needle portion 327. Boththe hollow needle portion of target needle 305 and the needle portion330 of inner puncher 312 are preferably composed of stainless steel formost applications of the invention and are thus configured to be visibleusing fluoroscopy to assist insertion to the desire depth. The innerdiameter of target needle 305 is further selected to allow the removableinsertion of a guidewire.

Target needle 305 and inner puncher 312, in this illustrative example,are further configured with a positive attachment comprising athreaded-type connection or, as shown in FIGS. 3 and 3A, a rotatablyengagable bayonet-type lock. In this arrangement, a pin 321 radiallyextends from a distal portion of the target needle 305. Pin 321rotatably lockably engages with a mating slot 336 disposed in a lowerportion of the grasper 321 when the inner puncher 312 is fully insertedthrough the needle portion 327 of target needle 305. When thus locked,the inner punch 312 is substantially fixedly radially and axiallylocated within target needle 305. By anti-rotating the inner punch 312with respect to the target needle 305, the inner punch 312 is unlockedso it can be removed from the target needle 305.

Inner puncher 312 includes a sharpened portion 335 at the distal end ofthe needle portion 330 as shown. The needle portion 330 of inner puncher312 is configured (i.e., has sufficient length) so that the sharpenedportion 335 is exposed when the inner puncher 312 is inserted into thehollow needle portion 327 of the target needle 305 and locked intoposition.

In an optional arrangement for the target needle 305, an energy deliveryfunctionality is provided whereby an energy delivery unit (not shown)such as an RF (radio frequency) unit is operatively coupled to thedistal end of the target needle 305 and/or inner puncher 312. Suchenergy delivery functionality may be utilized to assist with skin orother tissue penetration or blood coagulation, for example.

In another optional arrangement, target needle 305 and/or inner puncher312 are arranged with one or more markers such as ultrasonic, magnetic,or other types of markers. Use of such markers may advantageously reduceor eliminate the need for fluoroscopic imaging in some applications ofthe invention.

FIG. 4 is a pictorial view of an illustrative K-wire 402 that isarranged to be inserted through the target needle 305 (FIG. 3) after theinner punch 312 (FIG. 3) is unlocked and removed. K-wire 402 functionsto allow one or more devices to be placed over it to a particularanatomical location. K-wire 402 includes a groove 406 which is alsoshown in the detailed view of FIG. 4A. Groove 406 is arranged as acircumferential notch in most applications of the invention and providesfor depth placement on a matched basis among the one or more devices.Accordingly, groove 406 is spaced at a specific depth relative to theend of the target needle 305.

K-wire 402 is constructed from stainless steel in a similar manner toconventional guidewires. K-wire 402 may alternatively include otherdepth markings such as circumferential markers (not shown) or bearranged to be radiopaque (i.e., not allow X ray or other radiation topenetrate) or include radiopaque sections. K-wire 402 is preferablyarranged as a disposable or single-use tool.

In an optional arrangement for K-wire 402, a circumferential band 412 isdisposed along its length as shown in FIG. 4B. Circumferential band 412provides for depth placement in a similar manner as groove 406, and mayalso be utilized to perform as a mechanical stop to limit theadvancement of the K-wire 402 through the target needle 305.

In another optional arrangement, K-wire 402 is arranged with one or moremarkers such as ultrasonic, magnetic markers or other marker types, forexample, to avoid the need for fluoroscopy.

FIG. 5 is a pictorial view of an illustrative K-wire clamp 505 that,when placed by an operator on a guidewire such as K-wire 402 (FIG. 4)near the tissue entry site, functions to stabilize the guidewire. Suchstabilization may be helpful to prevent further insertion of theguidewire beyond a desired depth and unwanted inadvertent movement ofthe guidewire.

K-wire clamp 505 is generally configured in a hinged clamp arrangementin most applications of the invention in which each clamp portion isbiased with a spring (e.g., a torsional spring) to provide a desiredlevel of clamping pressure on the guidewire. K-wire clamp 505 ispreferably arranged as a disposable or single-use tool.

In an optional arrangement for K-wire clamp 505A, a slip sensor 510and/or alarm transducer 517 are disposed along portions of the K-wireclamp 505 as shown in FIG. 5A. If slippage (i.e., relative movementbetween the K-wire clamp 505 and the guidewire) beyond a predeterminedthreshold is detected by slip sensor 510, then a signal over signal path522 triggers the alarm transducer 517 to transmit an alarm to an alarmreceiving location or alarm monitor (not shown). In such optionalarrangement, K-wire clamp 505A provides a positive indication such as avisual indicator (e.g., activation of a light source such as a lightemitting diode) or audible alarm (e.g., activation of a tone generatoror buzzer) in the event that the K-wire clamp is inadvertently opened(either completely or partially) or the guidewire slips. Slip sensor 510is alternatively arranged as a magnetic sensor orelectrical/resistance-sensing sensor, for example.

Referring to FIGS. 6, 6A, 7 and 7A, pictorial and detailed views of twoillustrative dilators are shown. FIG. 6 is a pictorial view of a firstillustrative dilator 605 that is arranged with a through channel thatslidably engages with a guidewire such as K-wire 402 (FIG. 4) and isinserted through the supraspinous ligament. When used alone or incombination with the second illustrative dilator 705 shown in FIGS. 7and 7A, dilator 605 progressively (or sequentially) dilates tissue tothereby enable insertion of devices through the dilated opening.

Dilators 605 and 705 are preferably radiopaque and arranged asdisposable, single use tools in most applications of the invention.Dilators 605 and 705 are typically constructed from stainless steel,titanium or similar materials. Dilator 605 includes a grip portion 607at the proximal end, which in this illustrative example, is arranged asseries of rings that alternate with recessed portions. Dilator 705 isarranged with a similar grip portion 707. A grip portion employingknurling or other material texturing may be alternatively utilized witheither or both dilators 605 and 705 in some applications of theinvention.

Dilator 605 includes a groove 611, for example a circumferential notch,that functions as a visible depth marker. Dilator 705 is similarlyarranged with a groove 711. Dilators 605 and 705 may optionally includeother markers such as ultrasonic, magnetic or other markers, forexample, to avoid the need for fluoroscopy.

Dilator 605 is arranged, in this illustrative example, with amid-line/orientation indicator such as a longitudinal groove 615 that isdisposed substantially along the entire length of the dilator (i.e.,from the proximal to distal end). Such mid-line/orientation indicatorprovides a visual marker that assists proper insertion of the dilator605. Dilator 705 is also arranged with a longitudinal groove 715 in asimilar manner.

Dilators 605 and 705 share similar construction and features but differin size, notably inside and outside diameters (ID and OD, respectively).The respective diameters are selected such that dilator 605 and 705 aremateably and slidably engagable (i.e., in a telescoping manner). In thisillustrative example, the OD of dilator 605 is 5 mm and the OD ofdilator 705 is 9.3 mm.

Dilator 605 includes a tapered portion 621 at its distal end in which aspinous process channel 626 is disposed. The spinous process channel 626is configured to align and/or mateably engage with a spinous process tothereby maintain a desired mid-line position of the dilator 605. Inaddition, the spinous process channel may be utilized to distract tissuewhereby a forward force is applied. A scalloped leading edge 630 isoptionally disposed at the tapered portion 621 of dilator 605 which isarranged to facilitate insertion of the dilator through the tissue whileminimizing tissue trauma.

Dilator 705 also includes a tapered portion 721 and a spinous processchannel 726 that are each configured in a similar manner as thosecorresponding features in dilator 605. A scalloped leading edge 730 ispreferably included along the far distal end of dilator 705.

The tapered portions 621 and 721 of dilators 605 and 705, respectively,are preferably sized, when inserted, to end on the anterior side of thesupraspinous ligament (which can be verified under fluoroscopy or othervisualization means such as ultrasound). Such arrangement is intended tominimize damage to the supraspinous ligament since any trauma tounderlying tissue is less consequential. Table 1 below providesillustrative key dimensions for dilators 605 and 705.

TABLE 1 Taper Taper Spinous Process Channel Length Angle Channel LengthTaper Dilator 605 0.250 in. 27 degrees 0.225 in. 27 degrees Dilator 7050.570 in. 17 degrees 0.530 in. 15 degrees

Dilators 605 and 705 are each optionally arranged to include an energydelivery functionality using an operatively coupled energy delivery unit(not shown) such as an RF (radio frequency) unit. In most applications,the energy is delivered through the tip of the dilator to assist withtissue penetration or coagulation.

In an alternative arrangement, a third dilator (not shown) is alsoutilized. Such third dilator is intermediately-sized between dilator 605and dilator 705. Accordingly, the third dilator is configured withappropriate inside and outside diameter dimensions to be slidablyengaged over the OD of dilator 605 and slidably inserted into the ID ofdilator 705, typically in a close-fitting arrangement.

In a second alternative arrangement, a longitudinally oriented,relatively narrow opening such as a slit (not shown) is disposedsubstantially along the length of dilator 605 and/or dilator 705. Such afeature enables the dilator to be removed from the guidewire withoutrequiring the retraction of the full length of the guidewire. Forexample, the dilator can be simply removed by passing the guidewirethrough the longitudinal opening to thereby clear an object or device atthe proximal end of the guidewire.

FIGS. 8, 8A, 8B and 8C show pictorial views of an illustrative mountingbracket 802 in various alternative arrangements. Mounting bracket 802functions to create a stable working platform by holding an elongateddevice such as a cannula in a fixed position. Mounting bracket 802 isgenerally positioned over the dilator 705 (FIG. 7) prior to theinsertion of a cannula. Alternatively, mounting bracket 802 may bepositioned after the insertion of the cannula.

Mounting bracket 802 is typically further attached to a stabilizingdevice (such as that shown in FIG. 10) using a dual mounting slotarrangement 805 as shown in FIG. 8, or a single mounting slot 807 inbase 809. The alternative mounting slot arrangements enable such astabilizing device to be attached to the superior or inferior ends ofmounting bracket 802 (using slot arrangement 805) or laterally (i.e.,left or right, using the mounting slot 807). The other end of thestabilizing device is typically fixedly attached to a table or otherimmobile object. In addition to slots, mounting through-holes arealternatively utilizable for some applications. In alternativearrangements, mounting bracket 802 is configured for attachment directlyto the patient (instead of, for example, a table-mounted stabilizingdevice) through use of adhesives or sutures for skin-mounting or viascrews or other mechanical fasteners for bone-mounting.

Base 809 may be optionally arranged to include unique markings which, inthis illustrative example, are arranged as dots 811. For example,radiopaque markings or conventional visible markings are usable toassist with alignment, depth control, or mating with other discretedevices or tools. Alternatively, the markings may be arranged usingultrasonic, magnetic or other marker-types, for example, to avoid theneed for fluoroscopy.

Mounting bracket 802 thus facilitates the alignment of the cannula withthe spine so that an operator may select a desired trajectory andorientation of the cannula into the tissue. That is, mounting bracket802 with the associated stabilizing device provides positive control ofaxial, sagittal and coronal positioning of the interspinous spacer asimplanted by the present procedure and tooling.

As shown in FIG. 8A, mounting bracket 802A includes a single threadednut 813 that is rotatably coupled to an externally threaded cylinder 815having a cylindrically shaped passageway through which the tool isinserted. Cylinder 815 includes one or more longitudinally orientedslots 818 (FIG. 8) that enable the walls of the cylinder 815 to moveslightly radially inward to thereby provide a clamping force against theinserted tool when the nut 813 is tightened on the threads of thecylinder 815. The inner walls of the cylinder are optionally configuredwith projections or texturing to enhance the grip on the tool.Accordingly, nut 813 and cylinder 815 combine to form a receiving tube820 that surrounds and clamps a portion of the tool's elongated element(which is generally a tubular element).

In FIG. 8B, mounting bracket 802B includes an alternative dual nutdesign using a primary threaded nut 813B and a secondary lockingthreaded nut 814. Primary nut 813B is first tightened to fixedly clampthe tool's elongated element in the receiving tube 820. Secondary nut814 is then tightened to thereby lock the primary nut 813B in place.Other locking-type arrangements are also usable in some applications.For example, a nylon or other plastic insert (not shown) is disposedaround the inner threaded portion of nut 813 to provide anti-rotationcapabilities. A clutch-type mechanism (not shown) that slips uponreaching a predetermined torque or engagement travel may also beincorporated into the nut/cylinder arrangement. In addition, a positivelocking arrangement such as push-to-turn or lift-to-turn (as commonlyused in child-proof medicine containers) may be employed in thenut/cylinder mechanism in those applications where a positive lock andunlock feature is desirable.

Mounting bracket 802 is typically arranged, in most applications of theinvention, with a semi-spherical projection 825 that is disposed on abottom surface of the base 809 so that the spherical portion of theprojection 825 projects substantially downward when mounting bracket 802is oriented as shown in the FIGS. 8A and 8B. Projection 825 functions tosubstantially fill the area between the base 809 and the patient'stissue to thereby assist with stabilization of the mounting bracket 802.The semi-spherical shape of projection 825 provides for suchstabilization while simultaneously allowing rotation about three axes(i.e., yaw, pitch and roll) to facilitate setting of the trajectory of acoupled tool such as a cannula.

Base 809 of mounting bracket 802 is arranged in a stepped, or dualplane, configuration in the illustrative example shown in FIGS. 8, 8Aand 8B. Base 809 includes a planar portion 832 from which receiving tube820 upwardly projects and a planar portion 835 in which the one or moremounting slots are disposed. Planar portions 832 and 835 aresubstantially parallel while being offset to thereby enable mountingbracket 802 to be aligned with the patient's body particularly whenusing a non-orthogonal tool trajectory. The combination of the dualplane configuration with use of the projection 825 is particularlyadvantageous in many applications of the invention to provide stabilityfor the mounting bracket 802 over a range of tool trajectories.

An alternative configuration for the mounting bracket is shown in FIG.8C. There, mounting bracket 802C employs an angled base 809C that mayprovide additional flexibility for aligning mounting bracket 802C withthe body in some applications of the invention.

Mounting bracket 802 is preferably radiopaque and arranged as adisposable, single use tool in most applications of the invention.Mounting bracket 802 is generally preferred to be of rigid constructionto provide for stable orientation of the coupled tool. In mostapplications of the invention, base 809 is constructed of aluminum withthe nut 813 and cylinder 815 being formed from radiopaque plastic suchas polyphenylsulfone thermoplastic (sold under the brand Radel® R).Markers 811, when arranged as radiopaque markers, are formed usingstainless steel.

In an alternative arrangement, mounting bracket 802 is configured withmore than one receiving tube 820 (i.e., more than one nut/cylindercombinations). The other receiving tubes (not shown) may fixedly clampother tools, instruments or devices such as a laparoscopic camera orlight. The other receiving tubes may be oriented with the sametrajectory as receiving tube 820, or be oriented orthogonally or at someother trajectory with respect to receiving tube 820.

FIGS. 8D and 8E show pictorial views of an illustrative mounting tower850. Mounting tower 850 is used as an alternative to mounting bracket802 and similarly functions to create a stable working platform byholding an elongated device such as a cannula in a fixed position.Mounting tower 850 is generally positioned over the dilator 705 (FIG. 7)prior to the insertion of a cannula.

Mounting tower 850 is typically further attached to a stabilizing device(such as that shown in FIG. 10) using a dual mounting slot arrangement855 in a base 858 as shown in FIGS. 8D and 8E, or alternatively using asingle mounting slot or a plurality of mounting slots, i.e., three ormore (not shown). The alternative mounting slot arrangements enable sucha stabilizing device to be attached to the superior or inferior ends ofmounting tower 850 (using slot arrangement 855) or laterally (i.e., leftor right, using a mounting slot 855). The other end of the stabilizingdevice is typically fixedly attached to a table or other immobileobject. In addition to slots, mounting through holes are alternativelyutilizable for some applications. In alternative arrangements, mountingtower 850 is configured for attachment directly to the patient (insteadof, for example, a table-mounted stabilizing device) through use ofadhesives or sutures for skin-mounting or via screws or other mechanicalfasteners for bone-mounting.

Mounting tower 850 includes a pointing arrow 861 (such as a Cephaladindicator) that, in this illustrative example, is integrally formed withand laterally extending from base 858.

Mounting tower 850 is arranged with two pairs of spinous processgrippers indicated by reference numerals 864 and 866 in FIGS. 8D and 8E.Each spinous process gripper pair comprises two longitudinallyextending, opposing, pivotally-mounted legs. Opposing gripping surfacesare disposed at the distal ends of the legs and are arranged with aplurality of laterally inwardly extending serrated edges 869 in FIG. 8G.When the mounting tower 850 is in a fully deployed condition, spinousprocess grippers 864 are arranged to clamp to the superior spinousprocess and spinous process grippers 866 clamp to the inferior spinousprocess.

Mounting tower 850 further includes a superior depth post 870 and aninferior depth post 871 which project axially downward from the base858. Superior depth post 870 is disposed substantially between the legsof spinous process gripper 864. Inferior depth post 871 is disposedsubstantially between the legs of spinous process gripper 866. Posts 870and 871 function as depth stops. Thus, posts 870 and 871 are arranged tointerface with the posterior side of the supraspinous ligament so as tothereby limit the travel of the mounting tower 850 and position thespinous process grippers 864 and 866 in an appropriate orientation withrespect to the spinous processes. In this illustrative example, inferiordepth post 871 is shorter than superior depth post 870 so as to providesome angular freedom of motion in the plane including the longitudinalaxis of the supraspinous ligament.

Mounting tower 850 thus facilitates the alignment of the cannula andsubsequently utilized tools or devices with the spine so that anoperator may select a desired trajectory and orientation of the cannulainto the tissue. That is, mounting tower 850 with the associatedstabilizing device provides positive control of axial, sagittal andcoronal positioning of the interspinous spacer as implanted by thepresent procedure and tooling.

Mounting tower 850 includes a rotatably-mounted lowercylindrically-shaped collar 872 that extends axially upwards from base858. Collar 872 rotates about a spindle 873 having a receiving tube(i.e., lumen) therethrough. Collar 872 is operatively coupled using alinkage that is internally disposed in mounting tower 850 to the spinousprocess grippers 864 and 866. Collar 872 is biased against an internallydisposed spring to hold the collar 872 against an internally disposedstop. The stop prevents rotation of the collar 872 until the collar 872is pushed axially downward against the spring bias to thereby disengagefrom the stop and rotate freely.

Collar 872 includes surface features, for example knurling, to enhancethe operator's grip on the collar 872 when being manipulated.

An internally disposed spring normally biases the spinous processgrippers 864 and 866 outwardly as indicated by Position 1 in FIG. 8H.The internal linkage is arranged so that rotation of the collar 872causes movement of the spinous process grippers 864 and 866. Inparticular, clockwise rotation (when looking axially downward from theorientation of the mounting tower 850 shown in the figures) of collar872 causes relative inward motion of spinous process grippers 864 withrespect to spinous process grippers 866 as indicated by the arrows inFIG. 8H until the spinous process grippers 864 and 866 reach Position 2.As shown, the direction of motion of the spinous process grippers 864and 866 are in planes which are substantially parallel to the line 874defined by the longitudinal axis of pointing arrow 861 (i.e., Cephaladindicator).

Clockwise rotation of collar 872 further causes relative outward motionof the opposing legs in each pair of the spinous process grippers 864and 866 as indicated by the arrows in FIG. 8I. As shown, the directionof motion of each of the opposing legs are in planes that aresubstantially perpendicular to the line 874 which is defined by thelongitudinal axis of pointing arrow 861 (i.e., Cephalad indicator).

Typically, collar 872 is rotated clockwise to place the pairs of spinousprocess grippers 864 and 866 into a “ready” position prior todeployment. That is, the above-described inward motion of the spinousprocess grippers 864 and 866 reduces the size of the incision requiredto pass the spinous process grippers 864 and 866 into the operativeposition with respect to the spinous processes. In addition, theabove-described outward motion of the legs in each pair of spinousprocess grippers 864 and 866 ensures that a sufficient distance “D,” asindicated in FIG. 8I, is obtained for the legs to pass over the entirewidth of the supraspinous ligament as is required to clamp to thespinous processes.

FIG. 8J shows the position of the spinous process grippers 864 and 866as placed in the ready position through clockwise rotation of collar 872and positioned over the supraspinous ligament 875. Rotation of thecollar 872 in a counterclockwise direction allows the spinous processgrippers 864 and 866 to return to their normal outwardly-disposedposition as shown in FIG. 8K.

Mounting tower 850 further includes a rotatably-mounted uppercylindrically-shaped collar 880 as shown in FIGS. 8D-G and FIG. 8L thatis axially disposed above collar 872. In this illustrative example, theupper collar 880 is arranged to have a slightly larger diameter thanlower collar 875 to thereby allow the upper collar 880 to be disposed ina partially overlapping annular manner with respect to the lower collar875. Collar 880 is arranged in a similar manner as collar 872 withsurface features, such as knurling, to enhance gripping by the operator.

Collar 880 is threadedly engaged with the spindle 873 Clockwise rotationof collar 880 thus causes the spindle 873 to move axially upwards withrespect to the collar 880. An internally disposed linkage couplesspindle 873 to the spinous process grippers 864 and 866 and isconfigured so that the axial upward motion of the spindle 873 causes theopposing legs in each spinous process gripper to move inwards and clampthe spinous processes, i.e., the superior spinous process 881 andinferior spinous process 882. Continued clockwise rotation of collar 880by the operator functions to put sufficient clamping force “F,” as shownin FIG. 8L, on the spinous processes (collectively designated byreference numeral 884) by the spinous process grippers 864 and 866 tothereby hold the mounting tower 850 securely to the patient's spine.

In alternative arrangements, mounting tower 850 may be arranged with asingle set of spinous process grippers or more than two pairs of spinousprocess grippers. In addition, while rotatably-configured actuation isoften preferable, other mechanisms including levers and otherlinear-type actuators are also usable. Mounting tower arrangements usingmultiple receiving tubes are also contemplated as being desirable insome applications.

Mounting tower 850 is beneficially arranged, in most applications, as areusable, or multiple-use tool. Mounting tower 850 is generallypreferred to be of rigid construction to provide for stable orientationof the coupled tool. In most applications, mounting tower 850 utilizesmetal construction.

Mounting tower 850 may be optionally arranged to include uniquemarkings. For example, radiopaque markings or conventional visiblemarkings are usable to assist with alignment, depth control, or matingwith other discrete devices or tools. Alternatively, the markings may bearranged using ultrasonic, magnetic or other marker-types, for example,to avoid the need for fluoroscopy.

FIGS. 9, 9A and 9B are side, and two perspective views, respectively, ofan illustrative cannula 903. Cannula 903 is arranged to be fixedlyattached (i.e., clamped) in mounting bracket 802 (FIG. 8) to ensureproper orientation of the cannula 903 and delivery of the interspinousspacer in a desired manner. An internal lumen 906 in cannula 903 allowsimplants such as the interspinous spacer to pass through and is furtherconfigured in diameter and length to mate with devices and the presenttools. Such mating may be performed in a fixed arrangement using a clampor other removably coupling device (not shown). Cannula 903 therebyprovides alignment and depth control, for example, via mechanicalsurfaces, visual markers and other indicators as described below.Cannula 903 may also be used, in some applications of the invention, todistract (i.e., push forward) the spinous processes or tissue. It isnoted that the ID of the cannula 903 will typically vary according tothe size of the interspinous spacer being implanted.

Cannula 903 is preferably arranged as a disposable, single use tool inmost applications of the invention. Cannula 903 is typically constructedfrom a metal elongated tube 909 and includes a pointing arrow 912 (suchas a Cephalad indicator) at the proximal end that provides a referenceorientation along the mid-line towards the head. Cannula 903 includes atapered tip 915 at the distal end.

The proximal end further includes a counterbore 918 that extendspartially longitudinally inward (towards the distal end of cannula 903)and a flat 921 disposed on the inside wall of cannula 903 formed by thecounterbore 918. Counterbore 918 and flat 921 are examples of mechanicalsurfaces disposed on or within cannula 903 that function to providevisual or mechanical alignment. For example, counterbore 918 and flat921 provide alignment for devices or tools that are subsequentlyinserted into cannula 903 and/or provide a fixed insertion depth.

Tapered tip 915 includes one or more tapered spinous process channels924 which are configured to align and/or mateably engage with a spinousprocess to thereby maintain a desire position of the cannula 903. Inaddition, the spinous process channels 924 may be utilized to distracttissue whereby a forward force is applied. A scalloped leading edge 930is preferably disposed at the tapered tip 915 which is arranged tofacilitate insertion of the cannula 903 through the tissue whileminimizing tissue trauma. In particular, the scalloped leading edge 930may help to part the supraspinous ligament, for example, using arotating motion of cannula 903. Table 2 below provides illustrative keydimensions for cannula 903.

TABLE 2 Taper Taper Spinous Process Channel Length Angle Channel LengthTaper Cannula 903 0.100 in. 24 degrees 0.475 in. 6 degrees

Tapered tip 915 may be optionally arranged with an energy deliveryfunctionality using an operatively coupled energy delivery unit (notshown) such as an RF (radio frequency) unit. In most applications, theenergy is delivered through the tapered tip 915 of cannula 903 to assistwith tissue penetration or coagulation.

As an alternative to the pointing arrow 912 noted above, cannula 903 mayinclude a longitudinal groove or marking that is disposed along thelength, or a portion of the length of the elongated tube 909. Inaddition, cannula 903 is generally arranged to include unique markings,for example, radiopaque markings or conventional visible markings thatare usable to assist with alignment, depth control, or mating with otherdiscrete devices or tools. Alternatively, the markings may be arrangedusing ultrasonic, magnetic or other marker-types, for example, to avoidthe need for fluoroscopy.

FIG. 10 is a pictorial view of an illustrative flexible stabilizing arm1012. Stabilizing arm 1012 functions to stabilize one or more devices ortools with respect, for example, to the patient or operating table.Stabilizing arm 1012 further enables an operator to make adjustments tothe position and trajectory of coupled devices or tools. The stabilizingarm 1012 is preferably arranged as a reusable, or multiple-use tool.

Stabilizing arm 1012 includes a first attachment element 1018 and asecond attachment element 1021 as shown in FIG. 10. A flexible (i.e.,articulating) portion 1025 couples the first and second attachmentelements 1018 and 1021, respectively. As shown in FIG. 10, flexibleportion 1025 comprises a plurality of individual ball and socket typeelements that enable stabilizing arm 1012 to be manipulated by theoperator into a variety of shapes and configurations that are maintainedthrough friction between such elements. While other types of stabilizingarms (e.g., those having fewer degrees of freedom of motion) are alsousable in many applications of the invention, a flexible stabilizing armsuch as that shown in FIG. 10 is generally preferred.

First attachment element 1018 is arranged to be removably coupled to atool or device holding device such as mounting bracket 802 (FIG. 8). Asshown in FIG. 10, first attachment element 1018 comprises a threadedscrew 1028 having a plurality of gripping ridges 1030 extending radiallyoutward to facilitate threaded screw 1028 to be tightened by hand (i.e.,without requiring the use of tools) into the screw receiving portion1033 of first attachment element 1018. Screw shank 1036 is arranged toengage with a slot or through-hole in mounting bracket 802 to therebyfixedly and removably hold the mounting bracket 802 to the stabilizingarm 1012 when the screw 1028 is tightened.

Second attachment element 1021 is configured for removably ornon-removably coupling to a fixture such as an operating table, bed orother fixed or relatively immobile object. For example, secondattachment element 1021 is attached to an operating table usingmechanical fasteners such as screws or bolts inserted through holes orslots (not shown) in second attachment element 1021. In an alternativearrangement, second attachment element 1021 is configured for attachmentdirectly to the patient (instead of the operating table as provided inthe example above) through use of adhesives or sutures for skin-mountingor via screws or other mechanical fasteners for bone-mounting.

In another alternative arrangement, a third attachment element (notshown) is utilized. The third attachment element is disposed between thefirst attachment element 1018 and second attachment element 1021. Or,the second attachment element 1021 may be disposed between the firstattachment element 1018 and the third attachment element. Such a thirdattachment element advantageously enables, for example, two mountingbrackets (such as mounting bracket 903 in FIG. 9) to be presented on asingle stabilizing arm.

FIG. 11 is a pictorial view of a first illustrative interspinous knife1102 which functions to cut through tissue to enable the percutaneousaccess associated with the subsequent implantation of an interspinousspacer. Interspinous knife 1102 provides a plunge cut-type actionthrough the mechanical manipulation of a plunger 1107 by the operator ina pushing motion, typically by depressing the plunger 1107 with thethumb while gripping the handle portions 1109 with the fingers. Theplunge depth is both controlled and adjustable in this illustrativeexample as described below.

As shown in the detailed view of FIG. 11A, the plunger includes anelongated inner tube 1110 which is rotatably located in the elongatedouter tube 1115 of interspinous knife 1102 to thereby enable theoperator to make rotations of the cutting blades 1117 disposed at thedistal end of the inner tube 1110. As shown, blades 1117 are configuredin an “X” pattern, but other blade counts (including a single blade) andpatterns are usable depending on the specific requirements of anapplication of the invention.

Inner tube 1110 is arranged for slideable excursion through the outertube 1115 to effectuate the plunge cutting action. In variousalternative arrangements, plunger 1107 is biased against a spring forceprovided by a spring element (not shown) or is provided with a linearactuator such as a pneumatic actuator or spring loaded actuator. Inanother alternative arrangement, the plunge cut action is supplied witha mechanical advantage to increase cutting force. For example, a cam orlever type mechanism (not shown) may be utilized to increase the forceapplied by the blades 1117 by having the operator manipulate anactuating portion of the plunger through an increased distance.

A depth setting slide 1120 is disposed along a top surface of the handleportions 1109 of interspinous knife 1102 as shown in FIGS. 11 and 11B.Depth setting slide 1120 is arranged to move laterally in a slidingmotion from a first position as shown in FIG. 11 to a second position asshown in FIG. 11B. When the depth setting slide 1120 is in the firstposition, the plunge depth of the plunger 1107 is limited to nominally15 mm. When in the depth setting slide 1120 is in the second position,the plunge depth of the plunger 1107 is limited to nominally 20 mm. Itis emphasized that such plunge depth settings are illustrative and otherplunge depths may be selected according to the specific requirements ofan application of the invention.

Interspinous knife 1102 is preferably arranged as a disposable, singleuse tool in most applications of the invention. Blades 1117 areconstructed from stainless steel in most applications of the invention.The remaining components of interspinous knife 1102—including inner tube1110, outer tube 1115, plunger 1107 and depth setting slide 1120—aregenerally formed from a polymeric material (i.e. plastic) such as abiocompatible plastic.

In the illustrative example shown in FIGS. 11, 11A and 11B, the innertube 1110 is arranged to be rotated in an indexed manner. That is, themagnitude of rotation angles and the number of rotated positions of theinner tube 1110 are constrained with respect to outer tube 1115. Inother applications, an infinitely rotatable inner tube 1110 isutilizable. It may be particularly beneficial in some applications foran initial plunge cut to be performed followed by a second plunge cutafter the blades 1117 are rotated at an angle of 45 degrees to theinitial plunge cut.

Interspinous knife 1102 includes a widened shoulder feature 1121 that isconfigured to engage with the counterbore 918 and flat 921 in cannula903 (FIG. 9) when the interspinous knife 1102 is inserted through thelumen 906. Such engagement between the shoulder feature andcounterbore/flat thereby locates and aligns the interspinous knife 1102at the proper depth and orientation with respect to the cannula 903 andthe spine.

Interspinous knife 1102 is typically arranged with radiopaque orconventional visible markings that are usable to assist with alignment,depth control, or mating with other discrete devices or tools. Forexample, such markings can be used to indicate the longitudinal position(i.e., plunge depth) or orientation (i.e., rotation angle) of the blades1117. Alternatively, the markings may be arranged using ultrasonic,magnetic or other marker-types, for example, to avoid the need forfluoroscopy.

Interspinous knife 1102 may be optionally arranged with an energydelivery functionality using an operatively coupled energy delivery unit(not shown) such as an RF (radio frequency) unit. In most applications,the energy is delivered through the blades 1117 to assist with tissuepenetration or coagulation.

FIG. 11C is a pictorial view of a second illustrative interspinous knife1130 which functions to cut through tissue to enable the percutaneousaccess associated with the subsequent implantation of an interspinousspacer. Interspinous knife 1130 is usable to supplement interspinousknife 1102 (FIG. 11) or as an alternative to interspinous knife 1102.

Interspinous knife 1130 includes a semi-spherical depth stop 1135 thatis integrally disposed in a handle 1138. Depth stop 1135 is sized andarranged to interface with the counterbore 918 (FIG. 9) in cannula 903to thereby limit the cutting depth of interspinous knife 1130. Shaft1141 is sized in length to place the cutting blade 1145 at apredetermined distance from the depth stop 1135. Shaft 1141 is sized sothat cutting blade 1145 cuts to a nominal depth “D” of 15 mm, asindicated in FIG. 11D, from the anterior side of the supraspinousligament 875. Alternatively, shaft 1141 is sized so that cutting blade1145 cuts to a nominal depth of 20 mm.

Operation of the interspinous knife 1130 includes articulation ofinterspinous knife 1130 in cannula 903. In addition to a plunge-type cutthat is depth controlled by the depth stop 1135, interspinous tissue isalso cut by levering the handle 1138 so that the interspinous knifepivotally rotates about the semi-spherically shaped depth stop as afulcrum. The distal end of the interspinous knife thus sweeps through anarc so that the cutting blade 1145 is movable through a range ofpositions including that indicated by 1145′ in FIG. 11D.

Interspinous knife 1130 is preferably arranged as a disposable, singleuse tool in most applications of the invention. Cutting blade 1145 andshaft 1141 are constructed from stainless steel in most applications ofthe invention. The depth stop 1135 and handle 1138 of interspinous knife1130 are generally formed from plastic such as a biocompatible plastic.

FIGS. 12, 12A, 12B and 12C show various views and features of a firstillustrative interspinous reamer 1201 and its constituent components.Interspinous reamer 1201 is an optionally utilized tool in the toolingset described herein and functions to create a channel through which aninterspinous spacer is inserted by removing bone and other tissue whenrequired. Interspinous reamer 1201 is configured to remove both toughtissues including bone, as well as soft tissues. Interspinous reamer1201 enables percutaneous access in combination, for example, with themounting bracket 802 (FIG. 8) and cannula 903 (FIG. 9).

Interspinous reamer 1201 is configured to perform a tissue removal witha fixed diameter to thereby minimize damage to non-targeted tissue. Suchdiameter is preferably selected according to the size of theinterspinous spacer being utilized. Interspinous reamer 1201 is furtherconfigured for controlled depth of penetration as described below.

Interspinous reamer 1201 uses a two-piece construction comprising a corecutter 1208, as shown in FIG. 12, and a hole cutter 1212, as shown inFIG. 12A. Core cutter 1208 is inserted into hole cutter 1212 to therebyform the interspinous reamer 1201 as shown in FIGS. 12B and 12C. FIG.12B shows the core cutter 1208 being fully inserted into hole cutter1212, while FIG. 12C shows the core cutter 1208 being partially insertedinto the hole cutter 1212.

The interspinous reamer 1201 is generally operated in a two-stepprocess. A hole cut is made into the target tissue using hole cutter1212 which is followed by a core cut by the core cutter 1208 whichevacuates the tissue from the tube of the hole cutter 1212.

Core cutter 1208 is comprised of a flat bottom drill bit having asharpened tip 1215 and a forward serrated circumferential edge 1218. Anevacuation port 1221 is disposed on the face of core cutter 1208. Aspiral evacuation channel 1227 is disposed at the exit of the evacuationport 1221 for transporting removed tissue away from the working channelin the tissue when the interspinous reamer 1201 is coupled to a drill(such as a conventional bone drill, not shown) and rotated. Interspinousreamer 1201 is alternatively arranged to have an integrally incorporateddrill or to be coupled to a drill in a conventional manner.

Hole cutter 1212 is arranged as an elongated tube having a sharpeneddistal end, for example, arranged as a forward serrated circumferentialedge 1230, as shown in FIG. 12A. A plurality of laterally disposed holes1233 are arranged along the elongated tube of hole cutter 1212 to enablecleaning or evacuation of removed tissue into a cannula.

Core cutter 1208 and/or hole cutter 1212 are typically marked to allowfor controlled penetration depth. Alternatively, core cutter 1208 and/orhole cutter 1212 can be constructed to include a mechanical lock orpositive stop to physically limit or control penetration depth. Forexample, core cutter 1208 and/or hole cutter 1212 may include a lateralprojection that positively engages with the counterbore 918 (FIG. 9B) incannula 903 (FIG. 9) to function as a stop to limit penetration beyond apredetermined depth.

Interspinous reamer 1201 is typically arranged with radiopaque orconventional visible markings that are usable to assist with alignment,depth control, or mating with other discrete devices or tools.Alternatively, the markings may be arranged using ultrasonic, magneticor other marker-types, for example, to avoid the need for fluoroscopy.

Interspinous reamer 1201 may be optionally arranged with an energydelivery functionality using an operatively coupled energy delivery unit(not shown) such as an RF (radio frequency) unit. In most applications,the energy is delivered through the distal ends of core cutter 1208and/or hole cutter 1212 to assist with tissue penetration orcoagulation. In an alternative arrangement, interspinous reamer 1201 isconfigured as an over-the-wire tool using a centrally disposed lumen inthe core cutter 1208.

In most applications, interspinous reamer 1201 is beneficially arrangedas a reusable, or multiple-use tool.

FIG. 12D is a pictorial view of a second illustrative interspinousreamer 1225. As with the first illustrative interspinous reamer 1201shown in FIGS. 12, 12A, 12B and 12C, interspinous reamer 1225 is anoptionally utilized tool in the tooling set described herein andfunctions to create a channel through which an interspinous spacer isinserted by removing bone and other tissue when required. Interspinousreamer 1225 is configured to remove both tough tissues including bone,as well as soft tissues. Interspinous reamer 1225 is usable tosupplement interspinous reamer 1201 (FIGS. 12 and 12A-C) or as analternative to the interspinous reamer 1201.

Interspinous reamer 1225 includes a substantially spherically-shapedhandle 1228 that is disposed at the proximal end of an elongated shaft1231. At the shaft's distal end, a substantially cylindrically-shapedcutting element 1235 is disposed. Cutting element 1235 includes aplurality of radially outwardly projecting teeth disposed around thecylinder's surface in multiple rows as shown in the detailed view ofFIG. 12E.

Interspinous reamer 1225 includes semi-disc-shaped depth stop 1238 thatis disposed between the handle 1228 and the proximal end of the shaft1231. Depth stop 1238 is sized and arranged to interface with thecounterbore 918 (FIG. 9) in cannula 903 to thereby limit the cuttingdepth of interspinous reamer 1225. Shaft 1231 is sized in length toplace the cutting element 1235 at a predetermined distance from thedepth stop 1238. Shaft 1231 is sized so that cutting element 1235 cutsto a nominal depth “D” of 15 mm, as indicated in FIG. 12F, from theanterior side of the supraspinous ligament 875.

Interspinous reamer 1225 is typically arranged with radiopaque orconventional visible markings that are usable to assist with alignment,depth control, or mating with other discrete devices or tools.Alternatively, the markings may be arranged using ultrasonic, magneticor other marker-types, for example, to avoid the need for fluoroscopy.

Interspinous reamer 1225 may be optionally arranged with an energydelivery functionality using an operatively coupled energy delivery unit(not shown) such as an RF (radio frequency) unit. In most applications,the energy is delivered through the distal end of the cutting element1235 to assist with tissue penetration or coagulation. In an alternativearrangement, interspinous reamer 1225 is configured with a centrallydisposed lumen and utilized as an over-the-wire tool.

In most applications, interspinous reamer 1225 is beneficially arrangedas a reusable, or multiple-use tool. Handle 1228 is generally preferredto be formed from a polymeric material (i.e., plastic) such as abiocompatible plastic. Shaft 1231, depth stop 1238 and cutting element1235 are typically formed from stainless steel.

FIG. 13 is a pictorial view of a first illustrative interspinous gauge1306 which primarily functions to measure the distance between twoadjacent spinous processes at an intended insertion point for theinterspinous spacer. An operator manipulates control lever 1314 todeploy feelers 1317 from the distal end of an elongated barrel 1322 asshown in FIG. 13A. A gauge (not shown) on the handle 1326 provides avisual indication of the separation distance between the feelers 1317.

In the illustrative example of FIG. 13, a pair of feelers are shown in adeployed position. In other arrangements, other numbers of feelers areusable. In addition, in some applications it may be useful to employ anarrangement where only one feeler is movable while the others remainfixed in position.

The gauge may be selected, for example, from a mechanical type gaugeusing a needle or pointer on a scale, or an electronic type gauge with anumerical readout using an LCD (liquid crystal display) or LED (lightemitting diode) array to indicate the distance between the feelers. Inthis latter case, the display typically is arranged to receive a signalfrom one or more sensors disposed on the feelers 1317. The sensor isgenerally selected from one of stain gauge, force-sensing resistor,potentiometer (e.g., linear potentiometer), magnetic sensor, rotationalencoder (where the angle of rotation is correlated to distance) oroptical sensor (e.g., phototransistor). Alternatively, in addition tobeing transmitted to the gauge, the sensor signal may be transmitted toa separate or standalone read-out device or display.

In typical applications, interspinous gauge 1306 is arranged withradiopaque or conventional visible markings that are usable to assistwith alignment, depth control, or mating with other discrete devices ortools. Alternatively, the markings may be arranged using ultrasonic,magnetic or other marker-types, for example, to avoid the need forfluoroscopy. In another alternative arrangement, the markings include anindication of the interspinous spacer size or spacer catalog number tobe used with the interspinous gauge 1306 (where interspinous spacersizing is typically rounded, for example, to indicate an optimal or“best” size or catalog number). Instructions-for-use applicable to theinterspinous gauge 1306 may also be included in the markings in suchalternative arrangement.

Data provided to the operator on the gauge or via the markings isselected, for example, from one or more of position or orientation ofthe interspinous gauge 1306, deployment or distraction force beingapplied at the tool's distal end (e.g., through feelers 1317),deployment depth or level of the interspinous gauge 1306, or positionand orientation of the interspinous spacer.

Interspinous gauge 1306 is preferably arranged as a reusable, multi-usetool in most applications. Interspinous gauge 1306 further includes awidened shoulder feature 1330 that is configured to engage with thecounterbore 918 and flat 921 in cannula 903 (FIG. 9B) when theinterspinous gauge 1306 is inserted through the lumen 906 of cannula903. Such engagement between the shoulder feature and counterbore/flatthereby locates and aligns the interspinous gauge 1306 at the properdepth and orientation with respect to the cannula 903 and the spine.

Interspinous gauge 1306 is alternatively arranged to perform a varietyof optional functions including:

1) Measure distraction force. Interspinous gauge 1306 includes forcemeasuring components, such as sensors, that are disposed on the movablefeelers 1317 in this alternative arrangement.

2) Distract spinous processes. In this alternative arrangement, theoperator manipulates control lever 1314 to deploy feelers 1317 toperform the distraction function. In an optional configuration, thecontrol lever 1314 or other structures in the interspinous gauge 1306are equipped with distraction force-limiting or distractiondistance-limiting features.

3) Determine “Go” or “No Go” status for interspinous spacerimplantation. In this alternative arrangement, there are severalscenarios, for example, that interspinous gauge 1306 may be used toaddress: a) evaluation of poor bone quality result in bone deformationinstead of distraction; b) identification and/or treatment (e.g., smoothand/or remove) osteophytes that neighbor the point of contact, c)determination of inadequate spinous process thickness for interspinousspacer implantation, and d) other anatomical abnormalities that may beincompatible with the interspinous spacer or the tooling and/orprocedures used to implant it. The osteophytes are treatable usingdirected energy such as an RF energy source coupled to the feelers 1317,for example. Alternatively, mechanical abrasion may be applied throughthe feelers 1317. Feelers 1317 are generally provided with an abrasivesurface and further configured to oscillate through operation of thecontrol level 1314.

In some applications of the invention, interspinous gauge 1306 may alsobe arranged to include functionalities provided by the insertioninstrument shown in FIG. 14 and described in the accompanying text.

FIG. 13B is a pictorial view of a second illustrative interspinous gauge1350 that is alternatively used in place of the interspinous gauge 1306shown in FIGS. 13 and 13A. Interspinous gauge 1350 functions in asimilar manner to the interspinous gauge 1306 in that it measures thedistance between two adjacent spinous processes at an intended insertionpoint for the interspinous spacer.

An operator manipulates control lever 1355 by squeezing towards handle1357 to deploy feelers 1361 from the distal end of the elongated barrel1365. A gauge 1368, as shown in the detailed view of FIG. 13C, providesa visual indication of the separation distance between the feelers 1361.FIG. 13D shows the feelers 1361 in the deployed position in theinterspinous space formed between the superior spinous process 881 andinferior spinous process 882.

Interspinous gauge 1350 includes a widened shoulder feature 1370 that isconfigured to engage with the counterbore 918 and flat 921 in cannula903 (FIG. 9) when the interspinous gauge 1350 is inserted through thelumen 906 of cannula 903. Such engagement between the shoulder featureand counterbore/flat thereby locates and aligns the interspinous gauge1350 at the proper depth and orientation with respect to the cannula 903and the spine.

Extending axially upward towards the handle 1357 from the widenedshoulder 1370 is a marker area 1373 that is arranged to include one ormore markers to assist with depth control of the interspinous gauge intothe cannula 903. In typical applications, the markings are selected fromradiopaque or conventional visible markings. Alternatively, the markingsmay be arranged using ultrasonic, magnetic or other marker-types, forexample, to avoid the need for fluoroscopy.

Interspinous gauge 1350 is alternatively arranged to perform theoptional functions discussed above in the description of interspinousgauge 1306. Interspinous gauge 1350 is preferably arranged as areusable, multi-use tool in most applications.

FIGS. 14 and 14A are pictorial views of an illustrative insertioninstrument 1404. Insertion instrument 1404 functions to engage with,insert and deploy an interspinous spacer. Illustrative examples ofinterspinous spacers that are compatible with the insertion instrument1404 are described in applicant's co-pending U.S. patent applicationSer. No. 11/314,712, entitled “Systems and Methods for Posterior DynamicStabilization of the Spine” filed Dec. 20, 2005, the disclosure of whichis incorporated by reference herein. In the illustrative example shownin FIGS. 14 and 14A, the depicted interspinous spacer uses a deploymentmechanism which is activated by translation and/or rotation.

Insertion instrument 1404 uses the working channel that is preferablycreated by use of tools shown in FIGS. 3-13 and described aboveincluding, for example, target needle 305, K-wire 402, dilators 605 and705, mounting bracket 802, cannula 903, stabilizing arm 1012,interspinous knife 1102, optionally utilized interspinous reamer 1201,and interspinous gauge 1306. Insertion instrument 1404 is typicallyinserted through cannula 903 (FIG. 9) in mounting bracket 802 whichprovides alignment and depth control and, in particular, precise controlof the optimal axial, sagittal and coronal implant positioning.

Insertion instrument 1404 includes an elongated barrel 1410 that extendsfrom a handle 1416 to which deployment lever 1419 is pivotally disposed.Deployment lever 1419 is operatively coupled to extend and/or rotate aninner shaft 1422 that is disposed within barrel 1410 and extends justbeyond the distal end of barrel 1410. In this illustrative example, whenthe insertion instrument 1404 is engaged to an interspinous spacer,translation, and/or rotation of the inner shaft 1422 expands the movablyextendable elements of the interspinous spacer to thereby place it intoa deployed condition. Reversal of the translation or rotation places theinterspinous spacer back into a collapsed, un-deployed condition throughthe use of retraction lever 1463.

The deployment lever is alternatively arranged as a T-handle 1475 thatis disposed at the proximal end of insertion instrument 1404 and coupledto inner shaft 1422 as shown in FIG. 14F. In this alternativearrangement, rotation of the T-handle 1475 expands the interspinousspacer to thereby deploy it. In this alternative example, the T-handle1475 rotates in an indexed fashion through use of a laterally projectingpin 1481 from the T-handle axle that travels through a spiral track 1484to thereby create several discrete positions corresponding to varyingdeployment positions for the interspinous spacer. These positions “L”,“D”, and “DE” are visually indicated on the insertion instrument 1404corresponding to interspinous spacer states Load, Deployed, and DeployedExtended which are described below in the text accompanying FIGS. 31A-F.

It is emphasized that other interspinous spacer types and designs (i.e.,those that use other deployment mechanisms than that described above)are also usable with insertion instrument 1404. In addition, theinterspinous spacer is optionally pre-attached (typically by themanufacturer) to the insertion instrument 1404.

In most applications, insertion instrument 1404 is beneficially arrangedas a reusable, or multiple-use tool. In some applications of theinvention, it may also be desirable to combine the functionalitiesprovided by insertion instrument 1404 with those provided byinterspinous gauge 1306 (FIG. 13) into a single instrumentality or tool.

An outer clamping mechanism 1426 is also disposed at the distal end ofbarrel 1410 and extends outwardly. As shown in FIG. 14B, outer clampingmechanism 1426 includes an extended tang 1428 and a non-extended tang1430. Outer clamping mechanism 1426 is operatively coupled to a firstoperating lever 1435 as shown in FIG. 14. Operation of the firstoperating lever 1435 causes the outer clamping mechanism 1426 to lock tointerspinous spacer 1440 and, in particular, by the engagement oflateral ribs 1442 on the proximal end of interspinous spacer 1440 intocorresponding slots 1450 in extended tang 1428 and non-extended tang1430, as shown in FIG. 14C.

A second operating lever 1438 is operatively coupled to the distal endof inner shaft 1422 to which an inner clamping mechanism 1455 isdisposed. Inner clamping mechanism 1455 is comprised of opposing jaws(not shown) that are arranged to grasp a mating projection 1458extending normally rearward from the proximal end of the interspinousspacer 1440. Translation and/or rotation of mating projection 1458operates the deployment mechanism of the interspinous spacer 1440.Operation of the second operating lever 1438 causes the inner clampingmechanism to lock to projection 1458 on interspinous spacer 1440.

First and second operating levers 1435 and 1438 are each arranged toinclude both locking and unlocking functionality through forward andreverse operation of the levers, respectively. Accordingly, insertioninstrument 1404 is configured to both engage and disengage interspinousspacer 1440 through operation of the operating levers 1435 and 1438 bythe operator. Insertion instrument 1404 is further preferably configuredto re-engage with interspinous spacer 1440, for example, for furtherdistraction if required or to remove the interspinous spacer.

In typical applications, insertion instrument 1404 includes a variety ofmarkings, for example, to indicate various status conditions of the tooland the associated interspinous spacer 1440. In an alternativearrangement, the markings are selected as conventional visible markingsor may be radiopaque. Insertion instrument 1404 may also be optionallyarranged with one or more markers selected, for example, fromultrasonic, magnetic markers or other marker types to advantageouslyavoid the need for fluoroscopy.

A visual scale 1470 as shown in FIG. 14D is provided as one example ofmarkings to indicate the amount of interspinous spacer deployment and/orthe engagement condition (i.e., locked, unlocked, degree of lock etc.)of the interspinous spacer 1440 to the insertion instrument 1404. Visualscale 1470 thus provides quantitative feedback to the operator including“Go” or No Go” deployment status. FIG. 14E illustrates the deploymentpositions of the interspinous spacer 1440 indicated by the visual scale1470.

A zero depth indicator is provided by a widened shoulder feature 1473 oninsertion instrument 1404 that is configured to engage with thecounterbore 918 and flat 921 in cannula 903 (FIG. 9) when the insertioninstrument 1404 is inserted through the lumen 906 of cannula 903. Suchengagement between the shoulder feature and counterbore/flat therebylocates and aligns the insertion instrument 1404 at the proper depth andorientation with respect to the cannula 903 and the spine.

Insertion instrument 1404 may be optionally arranged with an energydelivery functionality using an operatively coupled energy delivery unit(not shown) such as an RF (radio frequency) unit. In most applications,the energy is delivered through the distal end of barrel 1426 (e.g.,through clamping outer mechanism 1426, the distal end of inner shaft1422, or inner clamping mechanism 1455) or via the coupled interspinousspacer 1440 to assist with tissue penetration or coagulation.

FIG. 15 is a pictorial view of an illustrative ligament splitter 1505that functions to split or part ligaments, such as the supraspinousligament, or other tissues. Ligament splitter 1505 is intended for usein the beginning steps of interspinous spacer implantation or duringsubsequent steps, i.e., one or more times, as required. The ligament istypically separated with ligament splitter 1505 along ligamentousstrands to minimize tearing, trauma, or other damage to the ligament.Such separation eases insertion of other devices, instrumentalities ortools (e.g., dilators 605 and 705 in FIGS. 6 and 7, and cannula 903 inFIG. 9). Separation is generally performed along a posterior, mid-lineapproach through the supraspinous ligament, although alternativeapproaches are also usable to thereby atraumatically part tissue.

Ligament splitter 1505 is beneficially arranged as a reusable, ormultiple-use tool in most applications of the invention.

Ligament splitter 1505 is constructed from an elongated tube 1510 withan internally disposed lumen 1516 through which a guidewire such asK-wire 402 (FIG. 4) is passed. The proximal end includes a handle 1508that is typically formed from a polymeric material (i.e., plastic) suchas a biocompatible plastic. The distal end of ligament splitter 1505, asshown in FIG. 15A, includes cutting blades 1522, which in thisillustrative example, are arranged as a pair of blades. In alternativearrangements, other blade counts may be used as required by a particularapplication of the invention. Cuttings blades 1522 are illustrativelyarranged with forward cutting surfaces and side cutting surfaces.

The distal end of ligament splitter 1505 is generally tapered, and inone preferred arrangement, the taper length is nominally 0.550 incheswith a nominal taper angle of 12 degrees.

The handle 1508 at the proximal end of ligament splitter 1505 isoptionally utilized. Such handle may be used to assist with theinsertion of ligament splitter 1505 in some applications. When thusequipped, the lumen 1516 is arranged to pass through the handle 1508.The optional handle is further arranged to include one or more markingsto indicate an orientation of the handle and/or ligament splitter 1505.Such markings are typically visible markings, but may also be configuredas radiopaque in some applications.

Ligament splitter 1505 may be optionally arranged with an energydelivery functionality using an operatively coupled energy delivery unit(not shown) such as an RF (radio frequency) unit. In most applications,the energy is delivered through the cutting blades 1522.

Ligament splitter 1505 is arranged, in most typical applications, toinclude a variety of markings, for example, to indicate orientationand/or depth of the ligament splitter 1505 when in use. In analternative arrangement, the markings are selected as radiopaque markersto provide one or more depth markers to thereby assist with thesplitting of the ligament. Ligament splitter 1505 may also be optionallyarranged with one or more markers selected, for example, fromultrasonic, magnetic markers or other marker types to advantageouslyavoid the need for fluoroscopy.

In an alternative arrangement that may be particularly useful in someapplications of the invention, two or more ligament splitters areutilized. Such ligament splitters share the above-described features andbenefits of ligament splitter 1505, but are sized sequentially larger(i.e., in diameter and/or length).

Referring now to FIGS. 16-20, several illustrations are presented whichshow various anatomical locations having relevance to the presenttooling and an inventive procedure for implanting an interspinous spacersuch as interspinous spacer 1440 in FIG. 14C.

The procedure is generally intended to be performed in an operating roomwith the use of fluoroscopy. However, in an alternative arrangement,ultrasound may be used instead of fluoroscopy to thereby allow theprocedure to be performed in a doctor's or clinician's office.

FIG. 16 provides an anteroposterior (AP) view of a lumbar spine 1604 andFIG. 17 provides a side view. Shown are the supraspinous ligament 1607(with ligamentous strands), superior spinous process 1608 and inferiorspinous process 1610. The inset illustration—indicated by referencenumeral 1620—shows a dilated portion 1625 of supraspinous ligament 1607.FIG. 17 also shows approach angle 1722 and zero point 1732.

A posterior mid-line approach (designated by reference numeral 1802)through the supraspinous ligament 1607, as illustrated in the AP view ofFIG. 18, is generally preferred. However, non-mid-line approaches arealso usable. For example, an approach 1902 just lateral of thesupraspinous ligament is shown in the AP view of FIG. 19. A pure lateralapproach 2002 is shown in the AP view of FIG. 20. In such alternativenon-mid-line approaches, the same tooling is often utilizable as withthe mid-line approach. In some cases, however, similar tooling isutilized with modifications to make the tooling longer, if necessary.The interspinous spacer implantation is alternatively performed usingpercutaneous or minimally invasive surgical approaches, or usingtraditional open surgery.

The procedure for implantation of the interspinous spacer preferablyincludes the creation of a working channel through dilation of tissue(including ligaments) using the tooling system shown in FIGS. 3 to 15and described in the accompanying text including, for example, targetneedle 305, K-wire 402, dilators 605 and 705, mounting bracket 802,cannula 903, stabilizing arm 1012, interspinous knife 1102, optionallyutilized interspinous reamer 1201, and ligament splitter 1505. Theprocedure overall is relatively rapid and enables a shortened recoveryperiod. Advantageously, the procedure is completely reversible at eachstep.

The interspinous spacer 1440 is preferably deployed into anun-distracted working space 1704 (FIG. 17) adjacent to the anterior wall1708 of supraspinous ligament 1607. However, interspinous spacer 1440 isalternatively deployed in a pre-distracted, or partially distractedspace.

FIGS. 21 and 21A show a flowchart of an illustrative procedure forimplanting an interspinous spacer using the tooling shown in FIGS. 3 to15. The description of the flowchart that follows makes reference to anumber of illustrations shown in FIGS. 22 to 33 below. The illustrativeprocedure starts at block 2104.

Blocks 2107 and 2112 include Step 1 in the illustrative procedure. Asindicated in block 2107, the target needle 305 (FIG. 3) is insertedthrough the supraspinous ligament 2223 (FIG. 22) to an appropriate pointbeyond its anterior side as confirmed through the use of fluoroscopy. Asindicated in block 2112, the inner puncher 321 (FIG. 3) is then removed.The result is illustrated in FIG. 22 where the target needle 305 isshown inserted to an appropriate depth past the zero point 2205 (whichis defined as the anterior side of the supraspinous ligament 2223). FIG.22 also shows that the inner puncher 321 is removed from the targetneedle 305.

Block 2115 in FIG. 21 includes Step 2 in the illustrative procedure inwhich the K-wire 402 (FIG. 4) is inserted through the hollow needleportion 327 of target needle 305. FIG. 23 shows the hollow needleportion 327 in cross section and the K-wire 402 inserted therethrough tozero point 2205. As shown in FIGS. 23A and 23B, K-wire 402 is insertedto an appropriate depth by aligning the groove 406 to the top of thewing 325. Alternatively, the appropriate depth may be determined usingfluoroscopy.

As indicated by block 2120 in FIG. 21, the target needle 305 is nextremoved, leaving the K-wire 402 in place.

Block 2126 in FIG. 21 shows an optional Step 3A in the illustrativeprocedure. K-wire clamp 505 (FIG. 5) is optionally utilized to preventinadvertent advancement of K-wire 402 while an operator determines theproper orientation of other devices that are installed over the K-wire402. Once such determination is completed, K-wire clamp 505 is typicallyremoved.

FIG. 24 shows K-wire clamp 505 being utilized on K-wire 402 to hold itat the zero point 2025 in supraspinous ligament 2223 (FIG. 22).

Block 2129 in FIG. 21 shows an optional Step 3B in the illustrativeprocedure where the ligament splitter 1505 (FIG. 15) is inserted overthe K-wire 402 (FIG. 4). Ligament splitter 1505 is optionally utilizedto split supraspinous ligament 2223 (FIG. 22) and/or other tissue (e.g.,non-ligament tissue when utilizing a lateral approach). Typically, theblades 1522 of ligament splitter 1505 are aligned with the superior andinferior spinous processes 1608 and 1610 (FIG. 16) to thereby beparallel with the ligamentous strands of the supraspinous ligament 2223(FIG. 22). A minimal amount of axial force is then imparted throughligament splitter 1505 to thereby part (i.e., split) the supraspinousligament 2223. Subsequent tools in the tooling system of the presentinvention may then be placed through such parted tissue.

In alternative arrangements, ligament splitter 1505 is utilized innon-posterior mid-line approaches such as those encountered with lateralprocedures and open surgeries (i.e., non-minimally-invasive surgeries).In addition, it is noted that ligament splitter 1505 may be beneficiallyused repeatedly, as required, in subsequent steps in the illustrativeprocedure described herein, or used solely in procedural steps thatoccur after the initial penetration of the supraspinous ligament.

Block 2133 in FIG. 21 indicates Step 4 in the illustrative procedure inwhich dilation of tissue is started. Here, the first illustrativedilator 605 (FIG. 6) is passed over the K-wire 402 to an appropriatedepth which is, typically, determined using fluoroscopy so that thetapered end portion 621 of dilator 605 is located just past the anteriorside of the supraspinous ligament 2223 (FIG. 22). In some applicationsof the invention, it may be helpful for the operator to rotate or rockthe dilator 605 using a back and forth motion as it is being insertedthrough the tissue. Markers, such as circumferential groove 611 andlongitudinal groove 615, described above, generally provide alignmentand/or proper depth control of dilator 605. In addition, the spinousprocess channel 626 on dilator 605, which is also described above, helpsto maintain a desired mid-line positioning of dilator 605 with respectto the supraspinous ligament 2223.

In alternative arrangements, dilator 605 is usable to distract thespinous processes (e.g., spinous processes 1608 and 1610 in FIG. 16).Either the spinous process channel 626 or tapered end portion 621 may beused in such cases.

FIG. 25 shows dilator 605 placed over K-wire 402 and inserted throughthe supraspinous ligament 2223 at the zero point 2025. FIG. 25A is anenlarged view which shows the tapered end portion 621 of dilator 605located just past the anterior side of the supraspinous ligament 2223.

After the insertion of the first dilator to start the tissue dilation inStep 4 of the illustrative procedure, the K-wire is removed. This isindicated by block 2136 in FIG. 21.

Block 2138 in FIG. 21 indicates Step 5 in the illustrative procedure inwhich dilation of tissue is continued. Here, the second illustrativedilator 705 (FIG. 7) is inserted over the first illustrative dilator 605to an appropriate depth so that the tapered end portion 721 of dilator705 is located just past the anterior side of the supraspinous ligament2223 (FIG. 22). The appropriate depth is determined using fluoroscopy,or alternatively, by aligning the proximal end of dilator 705 with thegroove 611 in dilator 605. In some applications of the invention, it maybe helpful for the operator to rotate or rock the dilator 705 using aback and forth motion as it is being inserted through the tissue.Markers, such as circumferential groove 711 and longitudinal groove 715,described above, generally provide alignment and/or proper depth controlof dilator 705. In addition, the spinous process channel 726 on dilator705, which is also described above, helps to maintain a desired mid-linepositioning of dilator 705 with respect to the supraspinous ligament2223.

In alternative arrangements, a third dilator (not shown) may beutilized. Such third dilator may be arranged to be: a) smaller indiameter than dilator 605; b) intermediately-sized between dilator 605and dilator 705; or c) larger in diameter than dilator 705. Use of sucha third dilator is optional in most applications, but may be helpful tominimize tissue trauma.

FIG. 26 shows dilator 705 placed over dilator 605 and inserted throughthe supraspinous ligament 2223 at the zero point 2025. FIG. 26A is anenlarged view which shows the tapered end portion 721 of dilator 705located just past the anterior side of the supraspinous ligament 2223.FIG. 26B shows the alignment of circumferential notch 611 with the topof the proximal end of dilator 705 as a means of assuring proper depthcontrol of dilator 705 with respect to dilator 605, zero point 2025, andsupraspinous ligament 2223.

After dilator 705 is positioned over dilator 605 to the appropriatedepth, as described above, dilator 605 is removed. Such removal isindicated by block 2140 in FIG. 21A.

Block 2143 in FIG. 21A indicates an optional Step 6 in the illustrativeprocedure in which the mounting bracket 802 (FIG. 8) is placed over thesecond illustrative dilator 705 (FIG. 7). Mounting bracket 802 ispreferably oriented in-line with the spine along the mid-line of thesupraspinous ligament. Such alignment may be achieved using fluoroscopyand/or using the visual and/or radiopaque markings described above inthe text accompanying FIG. 8.

In alternative arrangements where a lateral approach to the supraspinousligament is taken, the mounting bracket 802 is positioned with respectto the spine to enable such lateral approach.

FIG. 27 shows mounting bracket 802 placed over dilator 705. FIG. 27Ashows the orientation of the mounting bracket 802 with respect to themid-line 2707 of supraspinous ligament 2223.

Block 2143 in FIG. 21A further indicates an alternative optionalapproach in the illustrative procedure in which the mounting tower 850(FIG. 8D) is used instead of the mounting bracket 802. Here, themounting tower 850 is typically placed over the first illustrativedilator 605 (FIG. 6) after being placed into the “ready” positionthrough manipulation of the lower collar 872 in a clockwise rotation asdescribed above. The operator may wish to grasp the base 858 asnecessary to provide a counter-torque when rotating the collar 872, ifnecessary.

The pointing arrow 861 of mounting tower 850 is oriented superiorly andlowered over the proximal end of the dilator 605 while maintaining theexisting trajectory “T” effectuated by the dilator 605 as shown in FIG.27B and mid-line orientation as shown in FIG. 27D. Preferably, dilator605 is not further advanced into the interspinous space as the mountingtower 850 is positioned.

Once the distal tips of the spinous process grippers 864 and 866 areinserted through the incision, the operator begins to de-rotate thecollar 872 in a counterclockwise direction to allow the distal tips tobe inserted through the fascia just lateral of the supraspinous ligament2223. Mounting tower 850 is lowered until the superior depth post 870contacts the supraspinous ligament 2223. The operator should recheckthat the mid-line orientation and trajectory are satisfactorilymaintained.

Collar 872 is then fully de-rotated to enable the spinous processgrippers 864 and 866 to fully extend, as shown in FIG. 27E. The uppercollar 880 is then rotated clockwise to tighten the spinous processgrippers 864 and 866 and clamp the superior spinous process 1608 andinferior spinous process 1610, respectively. The operator should verifythat the mounting tower 850 is firmly clamped to the spinous processes.If adjustment is required, collar 880 is de-rotated counterclockwise andthen subsequently retightened.

The second illustrative dilator 705 (FIG. 7) is then placed over thefirst illustrative dilator 605 and through the center lumen of themounting tower 850. The second illustrative dilator 705 is inserted overthe first illustrative dilator 605 to an appropriate depth so that thetapered end portion 721 of dilator 705 is located just past the anteriorside of the supraspinous ligament 2223 as shown in FIG. 27F. Theappropriate depth is determined using fluoroscopy, or alternatively, byaligning the proximal end of dilator 705 with the groove 611 in dilator605. In some applications of the invention, it may be helpful for theoperator to rotate or rock the dilator 705 using a back and forth motionas it is being inserted through the tissue. Markers, such ascircumferential groove 711 and longitudinal groove 715, described above,generally provide alignment and/or proper depth control of dilator 705.In addition, the spinous process channel 726 on dilator 705, which isalso described above, helps to maintain a desired mid-line positioningof dilator 705 with respect to the supraspinous ligament 2223.

Block 2146 in FIG. 21A indicates Step 7 in the illustrative procedure inwhich a working channel is created by the insertion of cannula 903 (FIG.9) over the second dilator 705 (FIG. 7) and, if utilized, throughmounting bracket 802 (FIG. 8). The operator may rotate and/or rockcannula 903 during insertion in some applications of the invention. Insome alternative applications, the second dilator 705 may be used todistract the spinous processes using its tapered end portion 721.

Pointing arrow 912 (FIG. 9) of cannula 903 is aligned by the operatorwith the cephalad and mid-line of the supraspinous ligament. The markers811 disposed in mounting bracket 802 are also used to align the mountingbracket 802 with the mid-line of the supraspinous ligament. The cannula903 is advanced to an appropriate position where the spinous processeschannels 924 at its distal end is aligned and/or touching (i.e., mating)with adjacent spinous processes. In some applications, the appropriatedepth is achieved by having the operator align the top of proximal endof the cannula 903 with the circumferential groove 711 in the dilator705.

Once the cannula 903 is positioned, the operator locks the mountingbracket 802 to the cannula 903 by turning the nut 813 (FIG. 8). Seconddilator 705 is removed as indicated in block 2149 in FIG. 21A andmounting bracket 802 is then fixedly attached to a stabilizing devicesuch as stabilizing arm 1012 (FIG. 10).

FIG. 28 shows the operative relationship between the cannula 903,mounting bracket 802 and second dilator 705 where the top of theproximal end of cannula 903 is aligned with the groove 711 in dilator705. FIG. 28A is an enlarged view showing the cannula 903 insertedthrough the supraspinous ligament 2223 prior to the removal of dilator705. FIG. 28B is an enlarged view showing a desired alignment of thespinous process channels 924 with the superior spinous process 1608 andinferior spinous processes 1610. FIG. 28C shows a desired alignment ofthe markers 811 in mounting bracket 802 and pointing arrow 912 ofcannula 903 with the mid-line 2707 of the supraspinous ligament 2223.FIG. 28C also shows the operative relationship between the mountingbracket 802 and cannula 903 whereby the nut 813 is rotated (as indicatedby the reference arrow 2806) in order to clamp cannula 903 in areleasable fashion. Note that in FIG. 28C, a stabilizing device, such asstabilizing arm 1012 (FIG. 10) may be used but is not shown.

In cases where the mounting tower 850 (FIG. 8D) is utilized instead ofthe mounting bracket 802, the first illustrative dilator 605 is removedfrom the mounting tower 850. The cannula 903 (FIG. 9) is inserted overthe second illustrative dilator 705 and through the center lumen of themounting tower 850 as shown in FIG. 28D. The operator ensures thecorrect orientation of cannula 903 by aligning the cannula's pointingarrow 912 with pointing arrow 861 of the mounting tower 850. The cannula903 is advanced to an appropriate position where the spinous processeschannels 924 at its distal end is aligned and/or touching (i.e., mating)with adjacent spinous processes. In some applications, the appropriatedepth is achieved by having the operator align the top of the proximalend of the cannula 903 with the circumferential groove 711 in thedilator 705.

Block 2155 in FIG. 21A shows Step 8 in the illustrative procedure inwhich the interspinous knife 1102 (FIG. 11) is inserted into the cannula903. In most applications, the interspinous knife 1102 is inserted justto the distal end of cannula 903 by lowering the interspinous knife 1102until its shoulder feature 1121 (FIG. 11) bottoms out on the counterbore918 (FIG. 9B) of cannula 903. Alternatively, the interspinous knife 1102is inserted to a depth in cannula 903 that is determined using otherdepth indicators (including for example, visual markers), or to somefixed depth, or as indicated through use of fluoroscopy.

Once inserted into cannula 903 to the desire depth, interspinous knife1102 is generally operated to perform one, or in some applications morethan one, plunge cut. A typical plunge cut depth is 15 mm, althoughinterspinous knife 1102 may be arranged as shown in FIGS. 11 and 11B tobe adjustable so that other plunge cut depths are achievable, forexample, 20 mm in typical alternative arrangements. In alternativearrangements, other set plunge cut depths may be accommodated byinterspinous knife 1102, or an infinitely adjustable plunge cut depthmay be utilized.

In some applications of the invention where a second plunge cut isutilized, interspinous knife 1102 is typically adjusted so that thecutting blades 1117 (FIG. 11) are rotated to thereby enable the secondplunge cut to be oriented at a different angle from the first plungecut. With the interspinous knife 1102 shown in FIGS. 11, 11A and 11B,such adjustment is effectuated by rotating the inner tube 1110 to somedesired angle with respect to outer tube 1115. As noted above, suchrotation may be arranged using constrained rotation angles in an indexedmanner. Alternatively, interspinous knife 1102 may be rotated withrespect to cannula 903 to implement a rotated second plunge cut. Inalternative arrangements, interspinous knife 1102 may be configured touse a mechanically assisted plunge cut.

Upon completion of the desire plunge cuts, interspinous knife 1102 isremoved from cannula 903.

FIG. 29 shows the operative relationship between the interspinous knife1102 and cannula 903 when the interspinous knife 1102 is oriented to theappropriate depth through supraspinous ligament 2223. FIG. 29A shows thecutting pattern 2903 of the initial plunge cut. FIG. 29B shows thecutting pattern 2905 of the second plunge cut that is implementedthrough rotation of the interspinous knife 1102 with respect to thecannula 903. In the illustrative example shown in FIGS. 29A and 29B, thefirst and second plunge cuts are rotated 45 degrees with respect to eachother. As noted above, other rotation angles may be employed as may bedesired for a particular application of the invention.

Step 8 in the illustrative procedure may alternatively use interspinousknife 1130 (FIG. 11C) instead of interspinous knife 1102, or tosupplement the cuts made by interspinous knife 1102.

Block 2158 in FIG. 21 shows an optional Step 9 in the illustrativeprocedure in which interspinous reamer 1201 (FIG. 12B) is used, asneeded, to remove bone and/or other tissue in order to create a workingspace for an interspinous spacer. In typical applications where theinterspinous reamer is used, the hole cutter 1212 (FIG. 12A) is firstinserted through the cannula 903 (FIG. 9). Depth control may bemaintained, for example, visually or using mechanical indicators orstops as the hole cutter 1212 cuts the tissue. Core cutter 1208 (FIG.12) is then inserted into the hole cutter 1212 so that the hole cut ofthe tissue is followed by core cut by the core cutter 1208 to evacuatethe tissue from the tube of the hole cutter 1212. Depth control of corecutter 1208 is maintained visually or using mechanical indicators orstops, for example. Once the interspinous reamer 1201 completes thetissue cutting, it is removed from cannula 903.

In alternative arrangements, optional Step 9 in the illustrativeprocedure may use one or more interspinous reamers that are configuredto have different diameters and/or different distal end geometries toaccommodate a variety of tissue types.

Block 2161 in FIG. 21 shows Step 10 in the illustrative procedure inwhich the interspinous gauge 1306 (FIG. 13) is used to measure or sizethe appropriate interspinous spacer for a particular patient applicationby measuring the space between the spinous processes. The interspinousgauge 1306 is first inserted through the cannula 903 (FIG. 9) where thedepth and alignment of the insertion is typically determined through useof markers or via fluoroscopy. Alternatively, the widened shoulderfeature 1330 (FIG. 13) of interspinous gauge 1306 is configured toengage with the counterbore 918 and flat 921 (FIG. 9) in cannula 903when the interspinous gauge 1306 is inserted through the lumen 906 ofcannula 903. Such engagement between the shoulder feature andcounterbore/flat may thereby locate and align the interspinous gauge1306 at the proper depth and orientation with respect to the cannula 903and the spine.

The operator then manipulates the control lever 1314 (FIG. 13) toradially extend the feelers 1317 to touch adjacent spinous processes.The operator reads the distance between the distal ends of the feelerson a gauge or other visual readout on the interspinous gauge 1306.

FIG. 30 shows the interspinous gauge 1306 with deployed feelers 1317 inoperative relationship with the superior and inferior spinous processes1608 and 1610. The distance indicated by reference numeral 3006 isprovided to the operator on a gauge that is typically affixed tointerspinous gauge 1306 to assist in selecting the appropriately sizedinterspinous spacer. Note that the cannula 903 is not shown for the sakeof clarity in the illustration.

In alternative arrangements, Step 10 in the illustrative procedure mayinclude using the interspinous gauge 1306 to distract the spinousprocesses. Once the spinous processes are distracted, the interspinousgauge 1306 may be used as a measuring instrument as described above. Theinterspinous gauge 1306 may further be configured and used to measurethe force applied to the spinous processes during distraction.

Interspinous gauge 1306 may be further utilized during Step 10 in theillustrative procedure to provide “Go” and/or “No Go” information asdescribed above in the text accompanying FIGS. 13 and 13A. Suchinformation may be helpful in shortening the procedure and avoidingwasting product (e.g., interspinous spacer) and disposable tooling whenit is determined that a No Go condition exists.

Step 10 in the illustrative procedure may be alternatively performedusing interspinous gauge 1350 (FIG. 13B), as shown in FIGS. 30A and 30B.In this alternative process step, interspinous gauge 1350 is showninserted through cannula 903 (FIG. 9) as held in the alternativelyutilized mounting tower 850 (FIG. 8D) rather than the mounting bracket802 (FIG. 8). The operator firmly actuates trigger 1355 until resistanceis detected at the distal feelers 1361. As the supraspinous ligament mayrelax over time, the interspinous space measurement is preferably takenover a two to four minute time interval. A readout of the distancebetween adjacent spinous processes is provided on the gauge 1368. Theinsertion depth is read from the markings disposed on the marker area1373 with respect to the top of the cannula 903. In some applications,an accurate measurement is achieved after some degree of distraction ofthe spinous processes is performed.

Steps 11 and 12 in the illustrative procedure are described below withreference to FIGS. 31A-F which show the interspinous spacer 1440 (FIG.14) in various positions. Interspinous spacer 1440 comprises a body3102, actuator 1458, and cam lobes which are pivotally mounted to thebody 3102. A superior cam lobe 3105 is arranged to interface with thesuperior spinous process when the interspinous spacer 1440 is deployed.An inferior cam lobe 3110 interfaces with the inferior spinous processwhen the interspinous spacer 1440 is deployed.

FIGS. 31A and 31B show the interspinous spacer 1440 in the Undeployedposition in which the superior cam lobe 3105 and inferior cam lobe 3110are in a non-extended (i.e., collapsed) position and the actuator 1458is in a fully extended position with respect to the body 3102. FIGS. 31Cand 31D show the interspinous spacer 1440 in the Deployed position inwhich the superior cam lobe 3105 and inferior cam lobe 3110 are rotatedabout their pivots to extend laterally outward from the body 3102. Whenin the deployed position, the actuator 1458 is partially translated intobody 3102. FIGS. 31E and 31F show the interspinous spacer in theExtended position in which the superior cam lobe 3105 and inferior camlobe 3110 are further extended laterally from the body 3102. When in theextended position, actuator 1458 is fully translated into body 3102.

Referring again to FIG. 21A, block 2167 shows Step 11 in theillustrative procedure in which an undeployed interspinous spacer isloaded on the insertion instrument 1404 (FIG. 14). Referring to FIGS.31G-K, the operator first ensures that the inner shaft 1422 (FIG. 31H)of insertion instrument 1404 is fully retracted by appropriatemanipulation of deployment lever 1419 (FIG. 31G) so that the deploymentscale 1470 (FIG. 31I) indicates “L” for load. The operator then confirmsthe proper orientation of the interspinous spacer 1440 (FIG. 31J) withrespect to the insertion instrument 1404 by aligning the extended tang1428 (FIG. 14B) to the spacer 1440. Actuation of the second operatinglever 1438 (FIG. 31G) locks the inner clamping mechanism 1455 at thedistal end of the inner shaft 1422 to the actuator 1458 of theinterspinous spacer 1440 as shown in FIGS. 31H, 31J, and 31K. Next,actuation of the first operating lever 1435 (FIG. 31G) locks the outerclamping mechanism 1426 to the lateral ribs on the proximal end ofinterspinous spacer 1440. In an alternative arrangement of theinvention, it may be desirable to utilize only a single (e.g., theinner) clamping mechanism to lock the interspinous spacer 1440 to theinsertion instrument 1404. Once loaded onto insertion instrument 1404,interspinous spacer 1440 is ready to be implanted.

Block 2172 in FIG. 21 shows Step 12 in the illustrative process in whichthe interspinous spacer 1440 (FIG. 14) is deployed. The insertioninstrument 1404 (FIG. 14), with the interspinous spacer 1440 loaded asdescribed above, is inserted into cannula 903 (FIG. 9). The insertioninstrument 1404 is then advanced by the operator to a desired depthusing, for example, depth markings under fluoroscopy. Alternatively bybottoming the widened shoulder feature 1473 (FIG. 14) against thecounterbore 918 and flat 921 (FIG. 9) in cannula 903, insertioninstrument 1404 may be located at both an appropriate “zero” depth witha desired orientation, for example, with respect to the mid-line of thesupraspinous ligament. Such zero depth alignment is shown in FIG. 32.

Referring to FIG. 32A, the operator actuates deployment lever 1419 oninsertion instrument 1404 as indicated by arrow 3203 until thedeployment scale 3207 reaches “D” to thereby deploy the interspinousspacer 1440. The operator then confirms that the interspinous spacer1440 is properly deployed in its expanded and locked position, andextends deployment as necessary.

The above described steps advantageously implant the interspinous spacer1440 very precisely. Such precision prevents interspinous spacermigration, minimizes local fractures, and minimizes intrusion upon thedural canal by maintaining the interspinous spacer 1440 with theinterspinous space (i.e., a “safe zone”).

Optionally, the operator may reverse the extension of interspinousspacer 1440 by using retraction lever 1463.

Block 2176 in FIG. 21 shows Step 13 in the illustrative procedure inwhich the deployed interspinous spacer 1440 (FIG. 14) is extended to theproper height by the operator by actuating the deployment lever 1419 oninsertion instrument 1404 to thereby rotate the inner shaft 1422 (FIGS.14, 14B and 14C) and expand the interspinous spacer 1440. Such height isverified using various alternatives including, for example, visible,radiopaque, ultrasonic or magnetic markers. Upon the extension of spacer1440 to the proper height, insertion instrument 1404, cannula 903 (FIG.9) and mounting bracket 802 (FIG. 8) are removed. The illustrativeprocedure ends at block 2183 in FIG. 21A.

FIG. 32B is a pictorial view of the alternatively utilized insertioninstrument 1404 with an attached, loaded interspinous spacer 1440 in theUndeployed position. Insertion instrument 1404 is shown with cannula 903in the alternatively utilized mounting tower 850. FIG. 32C is apictorial view of the interspinous spacer in the Deployed position.

FIG. 33 is a pictorial view of the interspinous spacer 1440 in thedeployed condition after the insertion instrument is withdrawn. FIG. 34is a fluoroscopic image of the interspinous spacer 1440 (FIG. 14) in thedeployed condition.

The preceding merely illustrates the principles of the Invention. Itwill be appreciated that those skilled in the art will be able to devisevarious arrangements which, although not explicitly described or shownherein, embody the principles of the invention and are included withinits spirit and scope. Furthermore, all examples and conditional languagerecited herein are principally intended to aid the reader inunderstanding the principles of the invention and the conceptscontributed by the inventors to furthering the art, and are to beconstrued as being without limitation to such specifically recitedexamples and conditions. Moreover, all statements herein recitingprinciples, aspects, and embodiments of the invention as well asspecific examples thereof, are intended to encompass both structural andfunctional equivalents thereof. Additionally, it is intended that suchequivalents include both currently known equivalents and equivalentsdeveloped in the future, i.e., any elements developed that perform thesame function, regardless of structure. The scope of the presentinvention, therefore, is not intended to be limited to the exemplaryembodiments shown and described herein. Rather, the scope and spirit ofthe present invention is embodied by the appended claims.

1-345. (canceled)
 346. A method of implanting an interspinous spacerinto an interspinous space between a superior spinous process and aninferior spinous process of a patient, the method comprising:positioning an interspinous spacer in an undeployed configuration at anexternal posterior location relative to the interspinous space, theinterspinous spacer having a longitudinal dimension, wherein a superiorspinous process stabilizer and an inferior spinous process stabilizer ofthe interspinous spacer are in a collapsed position in the undeployedconfiguration; while in the undeployed configuration, moving theinterspinous spacer through a supraspinous ligament of the patient alongan insertion path toward to the interspinous space, wherein thelongitudinal dimension of interspinous spacer remains at least generallyaligned with the insertion path; and while at the interspinous space,extending the superior and inferior spinous process stabilizers from theundeployed configuration to a deployed configuration such that thesuperior and inferior spinous process stabilizers of the interspinousspacer interface with the superior and inferior spinous processes. 347.The method of claim 346 wherein extending the superior and inferiorspinous process stabilizers comprises extending the superior andinferior spinous process stabilizers while the longitudinal dimension ofthe interspinous spacer remains at least generally aligned with theinsertion path.
 348. The method of claim 346 wherein moving theinterspinous spacer through the supraspinous ligament comprises movingthe interspinous spacer through a midline portion of the supraspinousligament.
 349. The method of claim 346 wherein: positioning theinterspinous spacer comprises engaging the interspinous spacer to adistal end portion of an insertion instrument; extending the superiorand inferior spinous process stabilizers comprises the superior andinferior spinous process stabilizers in response to movement of theinsertion instrument, and the method further comprises disengaging theinterspinous spacer from the distal end portion of the insertioninstrument.
 350. The method of claim 346 wherein moving the interspinousspacer through the supraspinous ligament comprises passing theinterspinous spacer through a lumen of a cannula.
 351. The method ofclaim 350 wherein passing the interspinous spacer through the lumen ofthe cannula comprises passing the interspinous spacer through the lumenwith the longitudinal dimension generally aligned with a longitudinalaxis of the cannula.
 352. The method of claim 346 wherein theinterspinous spacer comprises a superior feature movably coupled to abody and an inferior feature movably coupled to the body, and whereinextending the superior and inferior spinous process stabilizerscomprises moving the superior feature superiorly such that the superiorspinous process stabilizer interfaces with the superior spinous processand moving the inferior feature inferiorly such that the inferiorspinous process stabilizer interfaces with the inferior spinous process.353. A method of positioning an interspinous spacer, the methodcomprising: positioning a distal end portion of a cannula proximate toan interspinous space between a superior spinous process and an inferiorspinous process, the cannula having a longitudinal axis extending in aposterior-anterior direction; delivering an interspinous spacer to theinterspinous space through the cannula with a longitudinal dimension ofthe interspinous spacer generally parallel to the longitudinal axis ofthe cannula; and deploying the interspinous spacer from a low profileconfiguration to an operative configuration while the interspinousspacer is at the interspinous space.
 354. The method of claim 353wherein deploying the interspinous spacer comprises deploying theinterspinous spacer while the longitudinal dimension of the interspinousspacer is generally parallel to the longitudinal axis of the cannula.355. The method of claim 353, further comprising coupling theinterspinous spacer to a distal end portion of a delivery device, andwherein delivering the interspinous spacer comprises passing theinterspinous spacer through the cannula with the distal end portion ofthe delivery device.
 356. The method of claim 355 wherein the deliverydevice comprises an inner shaft extending through a barrel, and whereindeploying the interspinous spacer comprises moving the inner shaftrelative to the barrel.
 357. The method of claim 355, further comprisingdisengaging the interspinous spacer from the delivery device andremoving the delivery device from the cannula.
 358. The method of claim353 wherein positioning the distal end portion of the cannula comprisespassing the distal end portion of the cannula through a supraspinousligament of a patient.
 359. The method of claim 353 wherein positioningthe distal end portion of the cannula comprises passing the distal endportion of the cannula laterally adjacent to a supraspinous ligament ofa patient.
 360. A system for implanting an interspinous spacer in aninterspinous space located anterior of a supraspinous ligament andbetween superior and inferior spinous processes within a patient, thesystem comprising: an interspinous spacer configured to be positioned atthe interspinous space, the interspinous spacer being deployable betweena low-profile delivery configuration and an implanted configuration, theinterspinous spacer having a longitudinal dimension; means for providingaccess to the interspinous space from a posterior side of thesupraspinous ligament; means for moving the interspinous spacer to theinterspinous space in a posterior-to-anterior direction along an implantpath while the longitudinal dimension of the interspinous spacer extendsalong the implant path; and means for deploying the interspinous spacerfrom the low-profile delivery configuration to the implantedconfiguration while the interspinous spacer is at the interspinousspace.
 361. The system of claim 360 wherein the interspinous spacercomprises means for interfacing with the superior spinous process andmeans for interfacing with the inferior spinous process in the implantedconfiguration.
 362. The system of claim 360 wherein the means forproviding access comprises to the interspinous space comprises a cannulahaving a working channel at least partially defining the implant path.363. The system of claim 362 wherein the means for moving theinterspinous spacer comprises a delivery device having a distal endportion configured to removably engage the interspinous spacer, whereinthe distal end portion carries the carrying interspinous spacer throughthe working channel.
 364. The system of claim 360, further comprisingmeans for creating an opening through the supraspinous ligament. 365.The system of claim 360 wherein the implant path extends through amidline portion of the supraspinous ligament.